A guy on a motorcycle is being chased by someone in a pickup truck. The motorcycle guy gets away from the truck and stops, but as the guy is peering over the hilltop, the truck plows into him, killing him.
Trish and Roger question Riana about what she was doing when she told her parents two different things.
Riggs is in Cahill's office and he figures out she's got a boyfriend. When he leaves he sees a file for Murtaugh in her cabinet and tries to get information, but he's unsuccessful.
Roger and Riggs are at the crime scene. Riggs is trying to get information about his file. He's unsuccessful. Bailey has a trainee named Montero who is giving the guys info.
They get an address from the motorcycle's GPS. Turns out the guy came from Dr. Cahill's house.The guy who died was her boyfriend.
Riggs and Murtaugh are questioning Dr. Cahill about the victim. They are uncomfortable.
Cahill decides she wants to help with the case which is why she didn't take the day off as Avery urged. Bailey comes in with the video from the helmet cam and Murtaugh sees a license plate. They search the plate owner's home and only find a camera...pointed directly at Cahill's house.
Cahill gets flowers delivered to her home from the stalker.
Murtaugh shows Avery all the pictures taken from the camera. Avery puts another therapist to look through Cahill's files to see who may be a suspect. The guy thinks it might be Kevin Flynn.
Riggs and Murtaugh visit Flynn who is a short little guy and end up fighting the guy. He's taken in. Cahill doesn't think he did it, so she goes in and talks to him and learns that Flynn was at his nana's house.
Riggs takes Cahill home. Someone is in her house and Riggs knocks him down. It's Cahill's husband. Riggs starts questioning Brad.
Trish searches through Riana's room and finds a fake ID. They are busted by Riana for being in her room. She tells them she has a job at a nightclub as a DJ and needed an ID to get in.
Riggs and Murtaugh talk to the therapist helper. They try breaking into Cahill's office, but she shows up. She gets a call from Brad, but she never told him to meet her anywhere. The killer knocks Brad into the street, but Riggs saves him from getting hit by a truck.
Riggs joins Cahill at a restaurant while on protective detail. She shares information about her husband. She knows the killer is watching and she wants Riggs to make him jealous. She thinks it's Brad. The killer is watching.
Riggs takes Cahill home. He goes after Brad while Murtaugh takes over detail. Murtaugh tells Riggs about why Cahill has a file on him. Bailey calls and tells Murtaugh the DNA test showed Dr. Levinson...the therapist helper was the one sending Cahill flowers.
Riggs turns around and heads back to Cahill'shouse. Murtaugh calls Cahill to get her out of the house. Levinson won't let her out of the house. As she tries to leave, Levinson is shot and killed by Montero.
Cahill recognizes him as a former patient. Montero turns on the fireplace gas. He threatens to kill them all. Murtaugh gets a sniper rifle and is going to shoot the guy, but Riggs gives the signal not to shoot. He shoots the guys hand instead which causes him to shoot the gun and the house explodes, but Riggs and Cahill get out and jump into the pool.
Riggs and Murtaugh talk about the case in the office. Riggs visits Cahill and she tells him she can't see him anymore as his therapist. He's not happy, but he seems to understand.
Trish and Roger are at the nightclub where Riana works to see her on the job.
Cahill comes into her office and finds Riggs on the ledge ready to jump. He doesn't want their sessions to end. She agrees to keep seeing him if he gets down from the ledge.