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.

The Threat Assessment Unit investigates the home of a young actress after she is frightened by an obsessed fan. Meanwhile, Beth receives an unsettling personal letter and Perry gains more access into her life.

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's former stalker methodically moves in on her, targeting those close to her in a deadly rampage.