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.