Stan throws a big weekend party to promote the Mystery Shack. Dipper makes clones of himself to impress Wendy. Mabel fights for the Party Queen title in honor of her two friends.
When Dipper and Mabel discover evidence that the reported town founder is a hoax, they set out to expose the historical cover-up and prove that Mabel's silliness is not a bad thing.
Dipper wants to correct a mistake he made in the past with assistance from a time machine. Mabel is overjoyed when she wins a pet pig at a fair.
After being challenged to a fight by Wendy's boyfriend Robbie, Dipper is shocked when his favorite Fight Fighters fighter, Rumble McSkirmish, comes to life to defend him, but Dipper soon loses control of Rumble and has to find a way to stop him from seriously injuring Robbie
Dipper is self-conscious that Mabel is taller than him and seeks a magic solution. Meanwhile Lil' Gideon takes advantage of Dipper's and Mabel's height discrepancy.
Dipper and Mabel go trick-or-treating in the summer and encounter a candy-loving monster who threatens to devour them if they don't bring him sweet things to eat.
Mabel bets Grunkle Stan that she will make more money at the Mystery Shack by treating people nicely than he does by being rude and cranky.
While Stan, Dipper, Mabel and Soos are falling in a bottomless pit, they tell stories to pass the time.
When Mabel befriends a cute merman trapped in the public pool, she's determined to help him out. Meanwhile, Dipper decides to volunteer as a lifeguard to see Wendy.
The twins discover a hidden room inside the Mystery Shack and compete over who should have it.
When Mabel discovers that her favorite boy band is actually a bunch of imprisoned clones, she sets them free, only to decide on keeping them for herself. Meanwhile, Dipper is convinced that Robbie plans to brainwash Wendy with a secret message hidden inside one of his songs.
When Grunkle Stan decides to run for mayor, Dipper and Mabel have their work cut out for them trying to turn their gaffe-prone uncle into the perfect candidate.
A new threat leads Mabel to venture into the enchanted realm of the unicorns. Meanwhile, Dipper learns an unexpected twist about the enigmatic Bill Cipher.
Grunkle Stan takes the kids with him on a road-trip to sabotage all the other tourist traps in Oregon.
Mabel decides to plan for her and Dipper's 13th birthday party. Meanwhile, Dipper and Ford venture below the town to find its most shocking secret.
Trapped in the apocalypse and menaced by villains new and old, Dipper finds himself in a race against time.
Dipper, Soos and Wendy must save Mabel from a strange new world, while Bill's forces plan their next move.
In the series finale, the Mystery Shack crew and townsfolk fight against Bill Cipher and his minions in a final stand to defeat them once and for all and save the town of Gravity Falls and the world.
Mabel takes matchmaking too far when she steals a love potion from a real Love God.
After agents Powers and Trigger take Stan into custody, Dipper and Mabel begin to wonder how much they actually know about their Grunkle Stan.