Bright finds his personal life in disarray after his sister's shocking actions. Now, he has to "take care" of her and protect his mother, Jessica, from a secret that could tear the family apart all over again. To distract himself, Malcolm takes on a new case and must find the killer behind a recent beheading in the city... and the only person he can turn to for help with the case is his father. Meanwhile, Martin returns to Claremont to a surprise new roommate and JT faces discrimination while on the job.

When a priest is found murdered in his place of worship, Bright grapples with its effect on his own trauma.

When the headmaster of Bright's alma mater is found murdered, he is forced to face a troubling secret from his past. Meanwhile, Jessica struggles with her decision to end things with Gil, Martin grows closer to Friar Pete and JT eagerly anticipates the birth of his baby.

Martin is delighted when a murder at Claremont Psychiatric brings the NYPD into his territory, allowing him direct involvement with one of Malcolm's cases. While working the same job, Ainsley's suspicion grows when she feels Malcolm may be hiding something from her. All the while, Malcolm and Ainsley must dodge their mother, who's wondering why they got rid of her favorite rug.

Malcolm and Ainsley both race to find the killer in the so-called "Debutante Slayings," but Ainsley's persistence has Malcolm worried about what her actual motive might be. While Martin is thrilled to see his daughter's passion in the field, Jessica suggests she and Ainsley take a vacation. Meanwhile, JT meets with his union rep to decide if he should file an official complaint against the cop who discriminated against him.

The team investigates the murder of an architect who was tasked with renovating a supposedly haunted hotel.

Malcolm focuses on a case in which a famous plastic surgeon is murdered; Martin gets a new job working in the infirmary with Dr. Vivian Capshaw; Jessica is surprised to learn her younger sister is in town.

When world-famous Europol profiler Simon Hoxley shows up in New York and claims that Major Crimes' current case is connected to the discovery of Endicott's body overseas, Bright fears he and Ainsley's secret is about to be exposed. Meanwhile, Martin gets to know Dr. Vivian Capshaw.

Despite Gil's fatherly concerns, Bright throws himself into a new case involving an escalating killer that has Edrisa's online vigilante group, known as the "Killabustas," trying to stop him. Meanwhile, Jessica realizes that she must dive deep into her past traumas in order to write a book and may need Gil's help to do it. Then, Martin's relationship with Dr. Capshaw intensifies.

As Malcolm distances himself from Martin, Jessica does the opposite, diving head-first into the past for the sake of her tell-all book. Meanwhile, Martin is desperate to get in touch with his son ahead of his imminent plans, as Dr. Vivian Capshaw grows increasingly suspicious. Meanwhile, the NYPD investigates a crime of passion.

After a terrifying incident at Claremont, Malcolm is in a race against time to track down multiple killers. The NYPD realizes someone close to home might be the key to finding them.

As the search intensifies for a serial killer on the run, so does Malcolm's tenacity, causing U.S. Marshal Emily Ruiz to kick him off the case. However, Malcolm doesn't back down that easily.