Det. Jack Larsen is a recent transfer to the Unit from New York City's homicide division, whose confidence, strong personality and questionable behavior has landed him in trouble before - but whose past behavior may also prove valuable in his new job. His boss, Lt. Beth Davis, is strong, focused and an expert in the field, driven by her traumatic personal experience as a victim. With the rest of their team, young but eager Det. Ben Caldwell and deceptively smart Det. Janice Lawrence, Larsen and Davis assess the threat level of cases and respond before the stalking and intimidation spirals out of control, all while trying to keep their personal obsessions at bay.
LAPD’s Threat Assessment Unit’s Lt. Beth Davis and Det. Jack Larsen search for a stalker with an affinity for fire. Beth meets with an exasperated college student who claims his former roommate is aggressively harassing him.
Beth, Jack and the TAU investigate after a teenage girl has a stalker break into her house, but quickly realize that she is not the one being targeted. Perry pays Beth an unsolicited visit at work.
When a bride is shot by a sniper during her wedding ceremony, Jack and Beth are called in to determine if her stalker has come back to haunt her.
Beth and Jack investigate an attack by a stalker who preys on his victims’ phobias. Beth learns a friend is seeing someone who, unbeknownst to both women, has ties to her.
While investigating a series of eerie threats, the TAU team discovers the victim’s house has a creepy history and is believed to be haunted. When the danger turns deadly, they spend Halloween night searching a wild costume party looking for a perpetrator long believed to be dead.
After a series of alarming occurrences befall a wealthy philanthropist, the TAU investigates her beleaguered ex-husband and his much younger girlfriend. Amanda threatens to reveal Jack’s dark past.
The TAU investigates the home of a young actress after she is frightened by an obsessed fan. Beth receives an unsettling personal letter and Perry gains more access into her life.
When a man's quiet suburban neighborhood and home are vandalized and his family is terrorized, he is forced to reveal his nefarious past to secure protection from the TAU.
After a series of harrowing attacks befall two seemingly random victims, the TAU desperately searches for a connection between them before the elusive stalker strikes again.
A high-profile athlete’s estranged wife is terrorized as her scandalous memoir is about to be published, and the TAU must investigate a long list of potential suspects to find the real perpetrator. Also, Beth finally reveals the painful details of her past
After the Mayor is victimized by a stalker, the TAU must determine if he is being harassed by one of his angry constituents or if a scandalous secret from his past is coming back to haunt him.
After a violent break-in at a popular anchorman’s home, Beth and Jack immediately investigate his previous stalker, but quickly learn it is a far more convoluted case. Meanwhile, Perry gets more insight into Beth’s past.
Beth and Jack must diffuse the threat against a female lifeguard and her loved ones when she becomes the obsession of a mysterious stalker.
When a popular high school coach claims he was attacked by a student with a crush on him, Beth and Jack investigate. Ray brings Perry into his plans to destroy Beth.
When a young woman is harassed by a mob of people, Beth and Jack realize they are dealing with a rare case of group stalking. Ray escalates his plan to isolate Beth from her closest allies.
Beth’s former stalker goes on a terrifying and deadly rampage targeting her inner circle as he methodically moves in on her.
Beth desperately fights for her life after her deranged stalker drags her to a remote cabin in Ojai, leaving Jack and Janice to frantically search for clues to their location. Also, the TAU waits for updates on Ben’s prognosis after he was shot.
Beth must make a tough decision about her future with the LAPD, while the TAU team investigates a suspect who could be linked to a string of recent murders. Also, Vicky’s ex-husband, Will, surprises her at work, prompting her to reveal to Beth the real reason she returned to Los Angeles.
Series Finale - Beth (Maggie Q), Jack (Dylan McDermott), Vicky (guest star Mira Sorvino) and the rest of the TAU team continue their search for a serial killer, and Vicky learns some startling information about her ex-husband.
A psychiatrist believes he is being stalked by a suicidal patient, but the TAU unravels a tangled mystery exposing the suspect and the great lengths he has undertaken to terrorize his victim. Beth’s private investigation into her own stalker leads to a stunning revelation.