At Vicky and Cormac’s wedding, Harry and Fergus interrupt an assassin’s kill and unwittingly bring about drastic consequences.

During an investigation of murders at a junk yard, Monk takes up painting and finds a patron.

A supermodel is killed and the suspects include her MMA fighter ex-boyfriend and an obsessed photographer who put a virus on her computer. Meanwhile, Rusty's interview in the Jane Doe case could jeopardize the people's case.

Dr. Lightman is convinced that one of his former protégé's students is a sociopath connected to a woman's disappearance, but everyone else is skeptical. Meanwhile, Torres and Loker help a high school teacher who thinks he saw an UFO.

Reese works the computer while Finch does the legwork with their latest target, a building superintendant who keeps too close an eye on his tenants. Meanwhile, Detective Carter may finally get a glimpse into one of their cases, so she can decide whether she wants to join the team.

While Cole gets into the holiday spirit for his first Christmas with Maya, Murtaugh hopes he can convince RJ to come back home from Costa Rica for the holidays. At the precinct, Cole and Murtaugh are saddled with a complicated burglary and home invasion case. Meanwhile, Avery's holidays are a bit blue, and Bailey is still trying to figure out her new partner.

Voight tells Halstead to remain impartial when the leader of a local mosque becomes a suspect in the bombing of an Army recruitment center.

Reddick digs deeper into Skinner's disappearance, while Linden and Holder try to keep their crime a secret and their investigation from going cold.

A supermodel is killed and the suspects include her MMA fighter ex-boyfriend and an obsessed photographer who put a virus on her computer. Meanwhile, Rusty's interview in the Jane Doe case could jeopardize the people's case.

Reese works the computer while Finch does the legwork with their latest target, a building superintendant who keeps too close an eye on his tenants. Meanwhile, Detective Carter may finally get a glimpse into one of their cases, so she can decide whether she wants to join the team.

Dr. Lightman is convinced that one of his former protégé's students is a sociopath connected to a woman's disappearance, but everyone else is skeptical. Meanwhile, Torres and Loker help a high school teacher who thinks he saw an UFO.

While Cole gets into the holiday spirit for his first Christmas with Maya, Murtaugh hopes he can convince RJ to come back home from Costa Rica for the holidays. At the precinct, Cole and Murtaugh are saddled with a complicated burglary and home invasion case. Meanwhile, Avery's holidays are a bit blue, and Bailey is still trying to figure out her new partner.