When three fifteen-year-old boys vanish from a Catholic school field trip, new Asst. Chief Mason orders Major Crimes to treat their disappearance as a critical missing. Meanwhile, Sharon receives more evidence that Phillip Stroh may be returning to Los Angeles.

While the search for the missing boys continues, the squad faces off with an untrustworthy priest, an angry ex-husband and threats from the FBI; Rusty startles Flynn and Sharon with a surprising request.

As Major Crimes continues to search for the remaining St. Joseph's Three, Sharon finds her personal life threatening her career.

While dealing with a difficult personal matter, Raydor continues to investigate the disappearance of the St. Joseph's Three, their relationship with an overly protective priest and the possibility that two of the 15-year-old boys could be killers.

As the case of the St. Joseph's Three leads to its unexpected conclusion, Sharon attempts to balance the case, the arrival of her family and her fast approaching wedding to Lt. Andy Flynn.

As the squad investigates the mysterious death of a second woman related to the Tackles case, and a new theory materializes, Sharon faces a health setback. Meanwhile, Gus reacts unexpectedly to Rusty's partial solution to their ongoing relationship problems.

While working two seemingly connected murders, the division suddenly uncovers a series of sexual assaults against servers from Tackles. As a new theory about the killer gathers steam, however, an unexpected twist throws Major Crimes off course and Sharon Raydor off- balance.

Sharon Raydor must make decisions related to her ongoing health problems while arriving at the solution of a series of murders and sexual assaults.

A surprise death in the law enforcement community seems to be the work of escaped serial killer, Phillip Stroh. Ricky Raydor helps the division with a difficult search for a Mr. and Ms. Bechtal, and Emily Raydor offers Rusty some sound advice.

Unable to locate Stroh in the present, the squad looks for answers in his distant past, hunting for the former Ms. Bechtal. Meanwhile, the squad struggles with Chief Mason, and Rusty grows frustrated with forced proximity to Gus.

In the penultimate episode, Phillip Stroh and his young British accomplice edge closer and closer to their end game, while Lt. Provenza continues to push Asst. Chief Leo Mason into pouring more resources into the case. Rusty digs up an important clue.

In the series finale, Lt. Tao, is stuck in a room with a potential bomb. Provenza finally identifies the real Ms. Bechtal, and Major Crimes comes face-to-face for the very last time with Phillip Stroh.