Shortly after sailors invade the streets of Boston for Fleet Week, a young girl is found dead. Frost's father, a Navy Admiral, comes to town, causing tension with his son. And, Maura goes on a date with Angela's mechanic.

The shooting of a community activist brings out a witness who's willing to testify. TV host Bill O'Reilly airs his disapproval of the police department.

Jane and Maura’s friendship suffers following the shooting of Maura’s biological father, gangster Paddy Doyle. Jane also finds herself in the middle of an Internal Affairs investigation. And her relationship with Agent Dean is exposed.

Young female professionals dressed as dolls are turning up dead on the public transit system, and Jane and Maura must piece together the clues. Angela implements new ideas for the café. And Jane learns more about how Casey was injured.

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 viral video of Jane jeopardizes her career and reputation; the squad tries to solve a murder case involving a conspiracy theorist.