CSI investigator Barry Allen awakens from a coma, nine months after he was hit by lightning, and discovers he has superhuman speed.
Barry escorts Iris to a university gathering honoring scientist Simon Stagg. When six gunmen storm the event, Barry changes into The Flash and tries to stop them. While he does save a man's life, he passes out before he can capture the robbers, which frustrates him. As Dr. Wells, Caitlin and Cisco scramble to find out what's wrong with Barry, Joe comes down hard on Barry for taking the law into his own hands and risking his life. Barry realizes that it wasn't six gunmen but a metahuman named Danton Black, who can make multiples of himself. Meanwhile, Iris becomes even more intrigued by the “red streak.”
As Barry and the team at S.T.A.R. Labs work to capture Kyle Nimbus, a.k.a. The Mist, a dangerous new meta-human with toxic gas powers, they revisit the painful night the particle accelerator exploded and killed Caitlin’s fiancé, Ronnie. Meanwhile, Joe decides to finally visit Henry in jail after all these years, but things take a dangerous turn when Kyle shows up looking to punish Joe for arresting him years ago. Meanwhile, Iris and Eddie continue to hide their relationship from Joe.
The Flash stops a robbery but the culprits get away after shooting a guard, and The Flash chooses to save the man instead of following the criminals. Joe shows Barry a book of suspects and Barry identifies Leonard Snart as the leader of the group. Snart revises his plan to steal the Kahndaq Dynasty Diamond and gets a boost when he gets his hands on a stolen “cold gun,” which could kill The Flash. Dr. Wells is furious when he finds out that Cisco built the cold gun without telling anyone and now it's missing. Meanwhile, Iris is getting the silent treatment from Joe because of her relationship with Eddie.
After a bomb goes off downtown, the army, led by General Eiling, rolls in and takes over the case, much to Joe's surprise. Suspicious, Joe tells Barry that he and his friends at S.T.A.R. Labs should look into the army's involvement. Wells informs the team that Eiling was experimenting on his men to turn them into super soldiers. Cisco confirms one of Eiling's soldiers, Bette Sans Souci, was at the bomb site. The Flash tracks her down and realizes that she's not setting off the bombs, she is a meta-human who can blow things up just by touching them. Meanwhile, when Joe learns Iris is writing about “the streak,” he tells Barry to make her stop. Barry realizes Iris won't listen to him so he decides to have The Flash pay her a visit.
The Flash faces a new meta-human named Tony, who can turn himself into girded steel at will. While Dr. Wells and Caitlin are concerned about Barry’s safety, Cisco comes up with a plan to take Tony down. Meanwhile, Iris’s blog on The Flash gets her into trouble, and Eddie witnesses Tony’s abilities firsthand and begins to ask questions that Joe doesn’t want answered. Joe asks Dr. Wells to help him solve Nora Allen’s murder.
The Flash goes up against Farooq aka Blackout, a metahuman who can harness electricity. During their battle, Farooq zaps The Flash and siphons all his electricity, leaving The Flash without his speed. Dr. Wells, Caitlin and Cisco work to reverse the effects on Barry, but their efforts are disrupted when Farooq comes banging on S.T.A.R. Labs doors in search of Wells, who he blames for his accident. Without Barry's powers to protect them, the group must figure out a way to save themselves from the metahuman. Meanwhile, Tockman manages a coup inside the Central City police department and takes several people hostage, including Joe and Iris. While Iris is sure The Flash will save them, Eddie has a trick up his sleeve.
Barry is thrilled when Oliver, Felicity and Diggle come to Central City to investigate a case involving a deadly boomerang.
Barry finds himself face-to-face with his nemesis, the man in the yellow suit, a.k.a. Reverse-Flash, who killed his mother. Barry is frustrated when the Reverse-Flash escapes, but Dr. Wells and Cisco come up with a plan to trap him. All they need is bait, so they turn to Dr. Tina McGee from Mercury Labs to help. Meanwhile, it’s Christmas at the West household and Iris is in full holiday cheer. Eddie gives her a surprising gift but also leaves her with a question that could change her life. Joe joins the search for the man in yellow and ends up in the crossfire. Caitlin finds Ronnie.
Leonard Snart AKA Captain Cold returns to Central City with a new hotheaded partner in tow – Mick Rory AKA Heat Wave. The duo plan to steal a multi-million dollar painting, but Cold has another agenda while in town – to set a trap for The Flash. Snart and Mick kidnap someone close to The Flash and threaten to kill them unless The Flash shows up for a battle of fire and ice. Barry tells Joe he isn’t sure he should take on Snart again after the casualties that happened the last time they fought. Meanwhile, Barry asks Dr. Wells, Caitlin and Cisco to help him double his training efforts so he’s ready for the Reverse Flash when he returns to Central City. Iris deals with the aftermath of Barry’s confession, and Cisco makes the CCPD a new shield.
Dr. Wells’ former protégée, Hartley Rathaway, returns to seek revenge on his mentor after being affected by the particle accelerator explosion. Now able to manipulate sound waves, the brilliant Rathaway is a dangerous threat to both Wells and The Flash. Meanwhile, Iris is thrilled when she’s hired by the Central City Picture News as their newest cub reporter. Unfortunately, her editor pairs her with a veteran reporter, Mason Bridge, who wants nothing to do with her. Cisco recalls his first day on the job at S.T.A.R. Labs when he met Hartley and Caitlin. Joe asks Eddie for a favor but asks him to keep it a secret from Barry.
Caitlin takes Barry out to a local karaoke bar to help them both find new loves. Caitlin strikes out but Barry meets a sports reporter and asks her out for a date. Cisco considers Hartley's dangerous offer. The team searches for Shawna, a meta-human with teleportation powers.
After Ronnie attacks a physicist, Barry and the team realize they need to go after Caitlin's fiancé who is now a dangerous meta-human. Barry struggles to balance his duties as The Flash and his relationship with Linda Park. Joe enlists Cisco's help to reinvestigate the murder of Nora Allen. General Eiling returns to Central City.
After the nuclear explosion separates Ronnie and Dr. Stein, Barry and the team believe both men are safe. Caitlin is thrilled to have her fiancé back and prepares to resume their life together while Dr. Stein returns to his wife. When General Eiling targets Firestorm, Ronnie and Dr. Stein must decide if they are safer together or apart. Mason Bridge tells Iris that there is something secretive going on at S.T.A.R. Labs. Dr. Stein gives Barry some important information about time travel.
Mark Mardon aka The Weather Wizard appears in Central City intent on avenging his brother Clyde's death, and sets his sights on Joe, who shot Clyde. When Mardon attacks Joe and Barry, Barry is able to super-speed them to safety but Mardon gets away. Barry warns Joe not to go after a meta-human alone but Joe doesn't listen and ends up in grave danger. Meanwhile, Cisco looks into the night the team captured the Reverse Flash and realizes something doesn't add up and begins to wonder whether Joe was right about Dr. Wells. Barry and Linda end up on an awkward double date with Eddie and Iris.
After going to the past, Barry talks to Harrison Wells about him time traveling and the consequences of changing the timeline. Meanwhile, the Flash learns that Captain Cold and Heat Wave have returned to Central City. This time Snart has brought along his baby sister Lisa aka Golden Glider to help wreak havoc on the city.
A copycat killer who goes by the name “The Trickster” starts setting off bombs in Central City. In order to stop the villain, Barry and Joe meet with the original Trickster, a criminal mastermind named James Jesse, who has been imprisoned for 20 years. Things quickly go from bad to worse when the Tricksters unite and take Henry prisoner. Meanwhile, Iris asks Eddie for help with a case and flashbacks show how Harrison Wells came up with the idea for the particle accelerator.
Barry is surprised when Felicity Smoak arrives from Starling City along with her boyfriend, Ray Palmer, who flies in as the Atom. They’ve come to visit S.T.A.R. Labs as Ray needs help with his suit. Their timing turns out to be fortuitous because it’s all hands on deck after a meta human named Brie Larvin unleashes hundreds of robotic bees to attack and kill her former co-workers, including Dr. Tina McGee. A group dinner with Barry, Felicity, Ray, Iris and Eddie turns into a disaster. Note: Flash 1x18 takes places before Arrow 3x18.
Joe and Cisco head to Starling City to continue their investigation of Dr. Wells. While in town, the duo enlists the help of Captain Lance, and Cisco meets the Black Canary, who asks him for a favor. Meanwhile, back in Central City, Barry races to catch a meta-human named Hannibal Bates who can transform himself into every person he touches – which includes Eddie, Iris, Caitlin and even The Flash.
Barry must deal with the Reverse Flash's latest threat to a member of the group. To make matter worse, Dr. Wells unleashes Grodd on the city in order to distract Barry and the team. Joe, Barry and Cisco head down into the sewers to catch Grodd but the gorilla quickly gets the upper hand after he kidnaps Joe. Iris and Barry have a heart to heart talk.
As Wells once again gets the upper hand on the S.T.A.R. Labs team, Barry realizes he needs to make a big move and reaches out to an old foe, Captain Cold, for help. Joe and Caitlin warn Barry that Cold can't be trusted. True to form, Cold has his own agenda that involves the meta-humans trapped in the containment cells. As things seem to be going from bad to worse, The Flash gets reinforcements - Arrow and Firestorm.
Wells presents Barry with a life-changing choice. Dr. Martin Stein and Ronnie Raymond return to help the S.T.A.R. Labs team with this final fight.
While in Wells' secret room, Barry learns about his battle with the Reverse-Flash in the future, as well as key moments in his life that include marrying Iris, a promotion at the CCPD, and that he created the artificial consciousness known as Gideon in the future. Barry, Caitlin, Cisco and Joe set a trap for Wells. Cisco uses himself as prey which puts him in grave danger. Meanwhile, Eddie makes a decision regarding Iris, which leaves Joe a bit unsettled.
Picking up months after the Singularity attacked Central City, Barry is still struggling to forgive himself for Eddie’s death. Concerned about putting his friends in danger, Barry has pushed everyone away and has chosen to protect the city on his own. When a meta-human named Atom Smasher attacks the city, Iris tells Barry that he needs to let his friends help him protect the citizens of Central City. Meanwhile, Cisco helps Joe with his Meta Task Force.
Jay Garrick, a mysterious man from Earth-2, appears at S.T.A.R. Labs with a dire warning about an evil speedster named Zoom, who is set on destroying The Flash. Barry and the team must decide if they can trust this stranger even as they face yet another powerful meta-human. Meanwhile, Joe must deal with a determined officer named Patty Spivot who wants to join his meta-human task force.
When Barry and the team find out Captain Cold has been kidnapped, they form an uneasy alliance with his sister, Lisa. However, Barry feels double-crossed when he finds out Snart is working with his father, Lewis Snart on a heist. Meanwhile, Joe is faced with a difficult decision.
Barry and the team look for another Firestorm match for Dr. Stein. When the team meets Jefferson “Jax” Jackson, Caitlin has her reservations about whether Jax is the right match for Dr. Stein. Iris surprises Joe while Barry and Patty grow closer.
Barry learns a new breacher, Dr. Light, has come through the portal and sets off to capture her. Jay tells Barry that Dr. Light was not a threat on Earth-2 and that Barry can reason with her. However, during a fight with The Flash, she blinds him and drops some shocking news about Zoom. Meanwhile, Barry and Patty go out on a date.
After recent events, Barry decides it’s time to confront Zoom and comes up with a dangerous plan. Caitlin sides with Jay and deems it too dangerous for Barry to engage with the speed demon. However, Iris shows her support and brings forth a surprising ally. We see what Earth-2 Harrison Wells’ life was like before coming through the breech.
Grodd returns to Central City and kidnaps Caitlin. Barry and team race to find her before it’s too late. Meanwhile, Cisco plans his first date with the new barista at Jitters, Kendra Saunders and Patty begins to suspect Barry is hiding something from her.
Vandal Savage arrives in Central City and sets his sights on Kendra Saunders. After Vandal attacks Kendra and Cisco, they turn to Barry for help. Realizing how dangerous Vandal is, Barry takes Kendra to Star City and asks Oliver and team to hide her until he can figure out how to stop Vandal. However, things quickly go from bad to worse when a man with wings AKA Hawkman shows up and flies off with Kendra. Meanwhile, Harrison develops a serum to make Barry run faster and asks Jay to test it out. This cross-over episode concludes on Arrow's season 4 “Legends of Yesterday” episode.
When Mark Mardon AKA The Weather Wizard returns to break Leonard Snart AKA Captain Cold and James Jesse AKA The Trickster out of Iron Heights, Barry must stop these rogues from taking over Central City during Christmas. Meanwhile, Joe and Iris meet Wally West.
Now that they've grown closer, Barry considers telling Patty that he is The Flash. Meanwhile, Joe and Iris try to get to know Wally, and the team hunts down a meta-human who can slow time itself.
When Cisco gets a vibe of Eobard Thawne, Barry and the team don’t believe it. But, after an attack at Mercury Labs, Christina McGee confirms that the Reverse Flash is back. Meanwhile, Iris and Francine share a nice moment that brings Iris closer to her brother, Wally.
Barry teams up with Wells to figure out a way to close the breaches, but they are distracted by a meta-human nicknamed Tar Pit who can transform into liquid asphalt. Iris is concerned for Wally's safety after she finds out about his drag racing hobby. When he refuses to stop she makes a bold move that puts her in danger.
Barry, Wells and Cisco journey to Earth-2 to rescue Wells’ daughter, Jesse from Zoom. Barry is stunned when he runs into Earth-2 Iris and Joe, but nothing prepares him for meeting Killer Frost and Deathstorm. Meanwhile, back on Earth-1, Jay has to take over the Flash’s responsibilities when a meta-human nicknamed Geomancer attacks Central City.
On Earth-2, the team races to find Zoom's lair and asks for help from the most unexpected source. Meanwhile, back on Earth-1, Caitlin rushes to perfect Velocity-9 so that Jay can stop the Geomancer.
When King Shark escapes from an A.R.G.U.S. holding tank, Lila and Diggle travel to Central City to warn The Flash. King Shark shows up at the West house and attacks Joe, Iris, Wally and Barry.
Having arrived in town intent on creating maximum chaos, Trajectory’s antics are misinterpreted as having been perpetrated by the Flash himself. Barry thus must quickly uncover the mystery of who is the girl under the mask — as well as what is driving her mad desire for speed and destruction.
After discovering the true identity of Zoom, Barry is more determined than ever to stop him. To increase his speed, Barry goes back in time to look for help from an arch nemesis.
Equipped with the tachyon device, Barry believes he is fast enough to stop Zoom and wants to open the breaches to catch him. Harry strongly advises against that plan but after Barry convinces him, Harry reveals that Cisco has the power to re-open the breach. Meanwhile, Hunter Zoloman’s painful story on Earth-2 is revealed.
A meta-human with super strength named Griffin Grey mistakes Harry for Earth-1 Harrison Wells and kidnaps him, demanding that Wells cure him from his current condition. Realizing another brilliant Wells could help track Griffin’s location, Barry asks Jesse to help. Meanwhile, Wally corners Joe about The Flash.
Zoom arrives back on Earth-1 intent on taking over Central City. Barry and Wells come up with a plan to stop Zoom once and for all but it’s extremely dangerous. Unsure if he should take the risk, Barry reaches out to both fathers for advice. Henry is adamantly opposed to Barry risking his life again but Joe thinks he can handle it which puts the two men at odds with each other. Meanwhile, Cisco is shocked when he vibes the Earth-2 villain Rupture, who happens to be his brother Dante’s doppelganger. Rupture came to this Earth seeking justice for Reverb’s death. Iris decides she’s finally ready to open up to Barry about her feelings for him.
With Barry gone, the team must figure out a way to handle the return of an old enemy - Girder. Realizing Girder is retracing his steps from his last attack, Iris volunteers to act as bait to trap him in S.T.A.R. Labs. Meanwhile, Barry fights to return to his old life.
After Zoom unleashes an army of Earth-2 meta-humans on Central City, Barry is shaken when he sees their leader is the Black Canary’s Earth-2 doppelganger, the Black Siren. Meanwhile, Wally takes to the streets to help The Flash stop the meta-humans, which worries Joe. Iris and Henry are concerned about Barry taking on Zoom.
With Barry in the speed force, Iris, Kid Flash, Joe, and Vibe have taken over protecting Central City. However, when a powerful armored villain threatens to level the city if The Flash doesn’t appear, Cisco makes a risky decision to break Barry out of the speed force. However, the Barry that comes out isn’t the same Barry that went in.
Barry has his hands full when he takes on a dangerous meta who can control technology, while also confronting an obstacle in his personal life: the ramifications of abandoning Iris for six months to balance the Speed Force. Meanwhile, Gypsy breaches in for a hot date with Cisco, but she gets annoyed when his work keeps them apart.
Barry and the team are hit by a string of bad luck and realize it is the handiwork of a new meta, Becky nicknamed Hazard, who has the ability to give others bad luck, while cashing in the benefits for herself. Meanwhile, Harry Wells returns to Earth-1 to give Wally a message from Jesse.
Cisco is shocked when Gypsy’s father, Breacher, shows up on Earth-1. Breacher takes an immediate disliking to Cisco and decides to hunt him. Meanwhile, Barry runs into his old nemesis, Ralph Dibny.
Having received an ominous threat from her old boss, Amunet, Caitlin fears that her past time as Killer Frost may be back to haunt her. Felicity comes to Central City to help the girls celebrate Iris’s bachelorette party, while Cisco, Joe and the guys take Barry out for a night on the town.
When collectors of Native American artifacts are attacked by a meta named Mina Chayton who can bring inanimate objects to life, Barry turns to a surprising ally for help. Determined to crack the identity of The Thinker, Harry enlists Cisco’s help to summon the ultimate think tank: “The Council of Wells’,” a roundtable of the brightest Harrison Wells’ from various Earths.
Barry comes face to face with DeVoe. Devoe’s past is revealed through flashbacks. Meanwhile, Iris puts the final touches on the wedding, which is a week away.
Barry and Iris’s wedding brings the gang together, but things go awry when villains from Earth-X attack the ceremony. All of the superheroes band together with help from their super friends like Citizen Cold, The Ray, Felicity Smoak, Iris West and Alex Danvers to take on their most formidable villains yet. Earth’s mightiest heroes – Green Arrow, Supergirl, The Flash and White Canary – lead their teams into battle to save the world.
Amunet kidnaps Caitlin and puts meta-dampener handcuffs on her to keep her from turning into Killer Frost. Amunet tells Caitlin she needs her to perform a tricky medical task and if Caitlin fails, Amunet will kill her. Meanwhile, The Thinker traps The Flash in a speedster-proof prison. With the clock ticking, The Team doesn’t have the time or resources to track both Caitlin and Barry so Iris is forced to choose who to save.
As Barry’s trial for the murder of Clifford DeVoe begins, Iris and Joe must decide how far they are willing to go to keep Barry out of prison.
Barry is occupied with his trial when a familiar villain returns to terrorize Central City, leaving Ralph to strive to defend the innocent. Can Barry keep his optimism alive in his new circumstances?
A meta who can shrink anything he touches battles Team Flash. Cisco and Ralph get caught in his crossfire and are shrunk to miniature versions of themselves. Cecile realizes her pregnancy has caused her to have temporary powers and discovers she can hear other people’s thoughts, which unnerves Joe. Meanwhile, Barry meets someone with a mysterious connection to Henry Allen.
After hearing that Amunet has struck a deal to buy all of the metahumans in Iron Heights, Barry must decide if he should expose his powers in order to save his cellmates. After a visit from an old friend, Ralph is reminded of his shady past and wonders if he’s really a changed man.
Barry is let go from CCPD, due to his connection with the DeVoe case. The team encounter another Bus Meta, named Izzy (aka The Fiddler), who has the ability to manipulate sound; a power, which the team hope she can use to help them in their fight against DeVoe.
When a nuclear bomb detonates in downtown Central City, Barry, Jesse Quick and Jay Garrick slow down time by entering Flashtime. As everyone in the city is frozen, the three speedsters push themselves to the breaking point to save the city and everyone in it.
Team Flash confront a new bus meta, Matthew Kim aka Melting Point. He has the ability to swap people’s DNA, so during a battle with Team Flash, he transfers Barry’s super speed to Iris. Now, with a new threat unleashed on Central City, Barry must act as the team leader while Iris takes on the mantle of superhero speedster in order to defeat their new foe.
Barry and Ralph take different approaches to finding the remaining bus metas before DeVoe gets to them. However, Ralph’s cavalier attitude frustrates Barry and the two clash over what it means to be a hero. Meanwhile, Breacher returns to ask Cisco for a favor.
When Barry and Team Flash find a way to enter The Thinker’s lair, Ralph considers crossing a dangerous line to defeat DeVoe. Meanwhile, Joe is concerned by Harry’s recent behavior.
When Barry needs help transporting a dangerous meta, he calls on a new friend for help – Leo Snart; Cisco becomes suspicious of Harry.
Barry and Team Flash team up with Gypsy to try to thwart Thinker’s plan. Meanwhile, Cisco and Gypsy have a heart to heart talk about their relationship.
With DeVoe’s Enlightenment device nearly complete, in order to disable it The Flash and his team must put their faith in an unlikely ally – Amunet Black. Meanwhile, Harry hits an all-time low when the “Council of Wells” kicks him out but then Cisco introduces him to the “Council of Harrisons.”
When DeVoe assaults an A.R.G.U.S. facility to complete his Enlightenment Machine, Barry realizes the only way he can stop him is if he allows Cisco and Caitlin to accompany him into the facility. Still shaken by Ralph’s death, Barry isn’t sure he wants to risk any more of his friends’ lives and considers taking on DeVoe solo.
Barry is living his dream life – his parents are alive, he’s asked Iris West on a date and he can finally be a normal guy as Central City has another speedster, Kid Flash, running around saving the city. When Barry starts forgetting parts of his old life, the Reverse Flash taunts his nemesis and tells him that there will be serious repercussions for Barry and the ones he loves if he continues to live in this alternate universe. In addition to losing his memories, his powers will also start to fade. When disaster strikes, Barry must decide if he wants to continue to live in this world as Barry Allen or return to his universe as The Flash.
Barry realizes the effects from Flashpoint are much greater than he thought. Barry meets new co-worker Julian Albert and is surprised by Julian’s immediate disdain for Barry.
Barry and Team Flash are thrilled to reunite with Earth-2 Wells and Jesse. Wells confides to Barry and Caitlin that Jesse has all the powers of a speedster and has been saving people on his Earth. He is concerned about her safety and wants them to talk her out of using her powers. Magenta, a new meta who can control metal, terrorizes the city.
Barry continues to train Jesse and when a new meta human, Mirror Master, appears on the scene he lets her tag along. Mirror Master has teamed up with his old partner, Top, and is looking for Snart to even a score. Jesse is quick to join the chase but defies one of Barry's orders which results in disastrous consequences.
Desperate to understand what is happening to her, Caitlin visits her mother, Dr. Tannhauser, a renowned biomedical researcher, in the hopes that her mother can provide some answers about Caitlin's growing meta-human powers. However, when Dr. Tannhauser treats her daughter like a test subject, Caitlin grows cold and brings up past wounds causing the two to have a major blowout. After a mysterious new meta-human attacks Central City, Barry tries to convince Julian to let him assist on the case.
When Wally starts having dreams about being Kid Flash, Barry realizes he has to tell Wally, Iris and Joe about what happened to Wally in Flashpoint in order to keep him safe.
When aliens called the Dominators attack Central City, Barry speeds over to Star City to ask the Green Arrow for help in stopping them. Realizing the battle against the Dominators is bigger than they thought, they track down the Legends of Tomorrow, and Barry and Cisco create a breach to bring back a secret weapon – Supergirl. Once all of the super friends are assembled, they come up with a plan to attack but a shocking secret related to Flashpoint is revealed and suddenly no one is sure who they can trust. Meanwhile, Wally wants to join the battle against the aliens but Iris tells him he’s not ready. Part 1 - Supergirl - S02E08 Part 2 - The Flash - S03E08 Part 3 - Arrow - S05E08 Part 4 - DC's Legends of Tomorrow - S02E07
With Alchemy and Savitar still looming threats, Barry is unable to focus on the Christmas holiday, and especially his relationship with Iris. Determined to stop Savitar, Barry goes to Earth-3 to get advice from Jay Garrick. Wally wants to help Barry fight Savitar and reveals that he’s been training with H.R, which doesn’t go over well with Barry. As Cisco faces his first Christmas without his brother Dante, old wounds are reopened.
Barry is tormented by his vision of the future where Iris is murdered by Savitar. When a criminal named Plunder shows up in Central City, Barry recalls the villain’s presence in his vision of the future and fears that if he catches Plunder, it will cement Iris’ fate. Confused about Barry’s hesitation to stop Plunder, Wally decides to step in as Kid Flash. Caitlin offers Julian a job.
H.R.’s past catches up with him when a bounty hunter with vibe powers named Gypsy arrives in Central City to bring him back to Earth-19 to stand trial for his crime. It turns out inter-dimensional travel is illegal on their Earth. H.R. surrenders but when Barry and Cisco find out that H.R.’s only hope would be to challenge Gypsy to a fight to the death, they intercede and Cisco offers to fight Gypsy instead.
Barry and the team at S.T.A.R. Labs work together to bring down Clive Yorkin, a criminal meta-human who is methodically killing people by causing them to decompose at an accelerated rate. Joe becomes his next target but it’s Iris who is caught in the crossfire. The Flash mentors Kid Flash and begins to elevate the newer speedster’s training to another level.
Barry, Caitlin, Cisco, and Julian voyage to Earth-2 on a rescue mission to save Harry from Gorilla City. As they trek through the forest, Barry and the team are immediately captured and taken to Grodd. Grodd tells them he needs their help to stop Solovar, the leader of Gorilla City, as Solovar wants to invade Earth-1. Back on Earth-1, Jesse and Kid Flash protect Central City and talk about their future.
When Grodd and his army of gorillas bring the battle to Earth-1, The Flash and team must find a way to stop them before they destroy Central City. Gypsy returns to join the fight. Jesse Quick decides she wants to stay with Wally on Earth-1.
While training with Barry, Wally starts to have visions of Savitar, which he hides from the team. A dangerous secret threatens Barry and Iris’ happiness.
Desperate to stop Savitar and save his friends, Barry turns to the speed force for answers. H.R. gives Jesse some advice.
Barry and team are surprised when Mon-El and Hank Henshaw arrive on their Earth carrying a comatose Supergirl who was whammied by the Music Meister. Unable to wake her up, they turn to Team Flash to save her. However, the Music Meister surprises The Flash and puts him in a similar coma, one that Team Flash can't cure. Kara and Barry wake up without their powers in an alternate reality where life is like a musical and the only way to escape is by following the script, complete with singing and dancing, to the end. This episode began in Supergirl S02E16.
Abra Kadabra, a criminal from the 64th century, comes to Central City, stealing from numerous tech companies and killing two guards. Gypsy returns, in pursuit of Kadabra, to avenge her partner. Kadabra offers the team the identity of Savitar in exchange for his freedom.
Barry travels to the future to find out Savitar’s still unknown identity in the hopes of saving Iris. Upon his arrival in 2024, Barry encounters future versions of his Team Flash friends, who, following the death of Iris, have become very different people, profoundly impacted by their showdown with Savitar. It will be up to Barry to infuse a sense of hope back into the team, as he proves to be hero his future friends have been waiting for. Meanwhile, back in 2017, the hunt for Killer Frost continues.
Barry and the team meet Tracy Brand, a scientist, who may be the key to stopping Savitar. Unfortunately, Killer Frost is also after Tracy so Team Flash must battle their old friend, which proves to be particularly difficult for Cisco. Joe and Cecile’s relationship takes a big turn.
Barry takes drastic measures to stop Savitar. Meanwhile, H.R. continues to push Tracy Brand to design the trap for Savitar and Killer Frost returns with an interesting proposal.
With only 24 hours left until Savitar murders Iris, Barry struggles to save the woman he loves and makes the choice to use any means necessary to do so. Realizing he has one option left to save her, The Flash turns to Captain Cold for help.
With nothing left to lose, Barry takes on Savitar in an epic conclusion to season three.
Caitlin uses her powers to save Barry but as her mother predicted, the effort unleashes her inner Killer Frost. Killer Frost goes on a rampage looking for Dr. Alchemy, kidnapping Julian and battling both The Flash and Vibe. Joe and H.R. have a heart to heart talk.
After an unexpected guest from the future appears at their home, Barry and Iris must figure out how to get her back to the future without disrupting the timeline.
As Barry helps his daughter, Nora, become a better speedster, he and Team Flash also track down a meta stealing high-tech weapons, only to cross paths with a new foe named Cicada, who is hunting the very same meta with nefarious intent.
After Cicada’s attack on The Flash, the team realizes they need to think outside the box to stop this dangerous new foe. Desperate to help her parents, Nora comes up with a plan that ultimately puts a member of Team Flash in danger. Meanwhile, Caitlin delves into her past.
Barry and Iris face the ultimate parenting test when Team Flash battles Spin, a savvy millennial armed with meta tech, and a dangerous agenda for their daughter, Nora. Ralph is feeling defeated until an unlikely source issues a challenge to help boost his confidence.
Nora lets something slip about the future that devastates Iris. In an attempt to distract his wife, Barry asks Iris to team up to stop a new meta, Rag Doll. Meanwhile, Caitlin learns something about her father.
Caitlin, Barry and Cisco learn something new about Caitlin’s father. Meanwhile, Iris and Sherloque follow a clue about Cicada.
While Nora grapples with unresolved anger over her father’s disappearance in the future, Barry and Team Flash must stop a powerful new meta, Weather Witch, from killing her own father, Weather Wizard.
Barry and Team Flash come up with a plan to stop Cicada. However, the plan calls for Barry and Nora to travel back in time to gather some key necessities. However, Barry hesitates, concerned about his daughter seeing certain parts of his life. Meanwhile, Sherloque takes his concerns about Nora to Iris, and Caitlin turns up a key asset in the fight against Cicada.
Part one of the crossover event with Arrow and Supergirl.
While Nora grapples with the revelation that Thawne killed her grandmother, Team Flash must stop the formidable team-up of a newly sprung from jail Weather Witch and Silver Ghost, a new meta-tech villain who can control engines and motorized technology. Meanwhile, Caitlin and Cisco discuss creating a meta-human cure.
During a battle with Cicada, Nora is severely injured. Due to Cicada’s dampening powers, Nora’s speed healing isn’t working, leaving Barry and Iris scared for their daughter’s future. Upset about his injured child, The Flash is filled with rage and confronts Cicada in a brutal battle. Meanwhile, Killer Frost keeps interfering with Caitlin’s work on the cure.
When Sherloque wants to use a memory machine on Barry and Nora to help gain access to Grace’s memories, Nora panics, fearing her parents will find out the secrets she’s been keeping from them. Nora secretly decides to use the machine on her own, which ends in disaster after she gets trapped inside Grace’s mind. Barry and Iris go in after their daughter and Iris is brokenhearted by what she finds. Meanwhile, Ralph tricks Cisco into going out for a night out on the town.
Barry and Ralph must go undercover as criminals in an illegal black market to purchase a device that could help them stop Cicada. Once inside, Barry and Ralph find their morality tested as they slip deeper into the criminal world, eventually having to choose between committing a crime, or losing the means to defeat one of their greatest foes. Meanwhile, Iris investigates a lead on Cicada’s whereabouts and ends up in a dangerous situation.