From among thousands of sailors in Boston during Fleet Week, an unknown sailor is suspected of two rapes and murders. Admiral Frost appears and he and his son Detective Frost do not see eye to eye. Policeman Rizzoli Jr. plays a part.

After the murder of much-loved community leader Elmore Gregory, Dante Morgan steps forward to identify the shooter as a gang leader, Terence Jones, also known as Little T. On the night before the trial, Dante leaves his police protected hotel room and is found dead the next day in a gang-ridden neighborhood with "snitch" written on his forehead. With the main witness out of the way, the only other evidence against Jones was obtained using information from one of Vince Korsak's confidential informants. When Vince says he can't produce him for the court, the judge gives the prosecution 48 hours of the case will be dismissed. Meanwhile, TV's Bill O'Reilly is in Boston to cover Little T's trial. Jane's mother Angela is a big fan and at a book signing she gives him Jane's cellphone number.

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.

The murdered man is in AA with Vince's ex-wife-he is not her husband. He lost his high-paying job in a pharmaceutical company and now is just a lowly pharmaceutical rep with a conscience, a past, and a plan for redemption.

A reclusive hoarder becomes the subject of an investigation into the murder of a city sanitation employee.