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. Guest star Billy Burke returns as FBI Agent Gabriel Dean, who hopes to rekindle his relationship with Jane.

The world of competitive dance turns deadly when the mother of a star performer is stabbed to death at a competition. Jane and the team search for clues, but they soon realize something is off about the woman's history. Korsak has his hands full when his stepson is accused of shooting a cop.

Jane attends her high school reunion and brings Maura along for the ride, but the fun is cut short when one of her old classmates turns up dead on the football field. Jane must focus on the past when she realizes everyone in her class is a potential suspect. Meanwhile, Korsak gets a visit from ex-wife Melody Patterson, who hopes he'll invest in her new business.

Boston Homicide teams up with the FBI after a bank manager is shot during a robbery. Jane's brother Tommy may be facing more trouble just as his relationship with Maura begins to grow. Tessa Thompson guest-stars as by-the-book FBI Agent Anna Farrell, who has a complicated history with Detective Frost.

When a community activist is gunned down, one brave witness comes forward to testify against a well-known gang member who is thought to have murdered 15 people. While the detectives work diligently to put him away, television host Bill O'Reilly comes to town for a book signing and criticizes the police department on-air. Roselyn Sanchez guest-stars as the gorgeous-and-driven Assistant District Attorney Valerie Hudson.

When a young man is killed in a jail bathroom right on the eve of his release, Jane and Maura get a nasty surprise when serial killer Charles Hoyt claims to have clues about the murder. Meanwhile, after months of preparation, Frankie Jr. is ready to take the detective's exam.

When a young, female dockworker is found dead, the team discovers that the dock has mob connections that may lead to Maura's biological father. Jane tries to evade sensitivity training. And Maura starts spending time with Jane's brother Tommy, much to Jane's dismay.

Jane and Maura delve into a family's background when a man is killed in what appears to be a mugging gone wrong. Meanwhile, a romantic and mysterious figure from Maura's past shows up, causing a rift when Jane suspects Maura is hiding something.

Jane and the team investigate what appears to be a modern-day witch hunt in Salem. Meanwhile, Frankie's old girlfriend returns to town with a surprise, and Jane has no problem speaking her mind about the situation.

A Revolutionary War re-enactment becomes the scene of a real killing when a soldier turns up dead. Maura's extensive knowledge of American history becomes important as she and Jane try to solve the case. And Maura's brilliant mother, Constance Isles, comes to Boston for an art exhibit.

Jane and Maura investigate after the coach of the Boston Pilgrims baseball team is found dead in the locker room. The death comes as a star player and the team owners battle for control of the team. Meanwhile, Jane's brother Tommy returns home after being released from jail.

When the daughter of a police officer is kidnapped in front of her younger brother, Jane and the team race to find the girl, fearing her abduction is connected to another case in which a young girl turned up dead only hours earlier.

Shortly after sailors invade the streets of Boston for Fleet Week, a young woman 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.

Jane and Maura's relaxing day at an outdoor spa is anything but when they discover the murder of a pregnant woman serving as a surrogate mother. Soon the hunt is on to find the baby's biological parents.

After taking a bullet in the Season Finale during a siege of the precinct, Jane Rizzoli is honored as a hero at a public event. The celebration is short-lived, however, when disaster strikes. The ensuing case reunites Jane with an old high-school flame, Sgt. Major Casey Jones (guest star Chris Vance), who may be just the person she needs to heal her emotional scars.