The ladies probe the killing of a husband and wife who were psychiatrists. Soon, an attendee of a medical-examiners seminar offers to help Jane and Maura in the case. Elsewhere, the Rizzoli family realize they may have connections to a pregnant stranger.

A boy band star returns to his roots for a show and winds up murdered. Jane and Frankie, who grew up with the victim, work hard to solve the case. Meanwhile, Jane and Maura must decide if it’s time to tell Angela the truth about Lydia’s pregnancy just as Angela prepares to throw her a baby shower.

When a statue breaks open to reveal a dead woman inside, Jane and Maura must find the killer quickly as the body count begins to rise. Back at headquarters, a new homicide detective is named to the squad. Meanwhile, Dennis Rockmond returns to Boston after disappearing on Maura and tries to woo her back. Lydia goes into labor.

When a man having breakfast in the Division 1 Café dies from poisoning, Jane and the team must quickly find the source as Angela and the irascible Stanley both come under scrutiny. Meanwhile, Tommy wants proof that he’s the biological father of Lydia’s baby as she returns to take the baby back. And Detective Korsak is reunited with one of his ex-wives.

A body is discovered in the church at TJ's christening; Jane almost abuses her power to protect Tommy; Lydia's fiancé threatens to take custody of TJ; budget cuts cause tension at the department.

A senator's daughter is found murdered; Tommy begins to slip back into old habits; Jane reveals some shocking news.