When it appears one of their own shot an unarmed man on a busy Boston subway platform, the team must fight to find the real killer while clearing their detective's name. But with Internal Affairs breathing down their necks, it becomes clear that the circumstances surrounding this shooting are anything but clear.
Jane and Maura find themselves submerged in the cutthroat, high stakes world of competitive bass fishing when a tournament-leading fisherman is killed. At the same time, Frankie is paying the price after losing a bet.
Jane and Maura are called out to the BCU "Body Farm" (an academic research facility dedicated to the study of human decomposition) when a murder victim is found buried in a shallow grave among the research corpses. Angela also has secrets she is keeping buried from Jane.
The good news is the team finds a witness to a murder. The bad news is he suffers from Prosopagnosia, commonly known as facial recognition blindness, and can't recognize the killer. The Rizzolis prepare for a visit from their scheming cousin Carlo.
When a 16-year-old girl is murdered and left in a cage, Jane and Maura must overcome the ethical dilemma of a psychiatrist and the stiff opposition of a fussy prosecutor to find the killer. Meanwhile, Jane has couch issues, and Frankie is seeing UFOs.
When the jeweler to Boston's super cool and famous dies, our investigation leads us to a member of the Isles family we've never met. And that leads us to a secret Maura has been keeping for almost all of her life.
The murder of a college student takes an odd turn when Jane and Maura discover he had 32 girlfriends. Uncovering who killed him and why leads them into a world of app developers, virtual boyfriends, and relationships built on lies. Meanwhile, Korsak finally introduces everyone to the new woman in his life.
After a body turns up in Boston with links to another murder in Los Angeles, Jane and Maura pack up their sunscreen and hop on a plane. With the girls out of town, Angela and Korsak plan a double date with Kiki and Ron.
Jane investigates the murder of a woman who is part of a fear club; Korsak and Nina find the hacker responsible for Jane's problems, but it causes more questions; Angela finds an engagement ring in Korsak's desk and tells Jane and Maura he is going to propose to Kiki. Angie Harmon's Daughter Avery plays a girl who raises money to buy a puppy.
When a quiet neighborhood is disrupted by a violent gun battle, Jane and Maura take the lead on the investigation and become involved in the mysterious world of Eastern European gang life; Maura becomes sick with a fever.
Korsak finds himself in a minefield, after a jogger hears an explosion and finds a severed finger. While the team investigates the victim after saving Korsak, he and Kiki discuss the dangers of the job, causing him to fear she will have doubts about marrying him. Meanwhile, Ron asks Angela to attend a Paris conference with him and Nina finds the woman targeting Jane and Maura, only to discover she has been released from jail.
Alice Sands, born into a distinguished law enforcement family, dropped out of the police academy while Jane was enrolled. Her fixation on Jane stemmed from being second in her class behind Jane, after having been the best at everything prior to then. She turned to running a drug ring, leading to her arrest and subsequent release from prison. Alice duped a fellow inmate into leaving together, but fled to Canada without her. Meanwhile, Korsak and Kiki finally get married, but the reception at the bar is interrupted by gunfire.