Jane Rizzoli and Maura Isles find themselves investigating a death that occurred during the re-enactment of of a Revolutionary War battle organized by a university professor, Dwayne Cravitz. They soon determine that far from being an accident, the shooting was from a sniper who was actually out to kill Cravitz. A DNA sample leads them to believe that the shooter is someone from his past. Maura meanwhile is thrown for a loop when her mother, the rich and beautiful Constance Isles, drops in for an unexpected visit. They have a strained relationship however with Mrs. Isles not quite sure how to be a mother to her daughter and Maura feeling intimidated and reduced to babbling in her presence.

When a warehouse fire kills a firefighter, Jane and Maura must investigate whether it was arson or an accident. But the investigation hits a snag when a hit-and-run leaves someone in the hospital.

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.