Boston detective Jane Rizzoli and medical examiner Dr. Maura Isles have each other's backs as they investigate their city’s grittiest and most puzzling homicides, from the Back Bay to back alleys. Some best friends shop together, some meet for Mojitos, some join book clubs. Rizzoli and Isles bust crime.

Jane deals with emotional and physical scars as old loves re-appear and her mother Angela deals with divorce. Meanwhile Jane's ex-con brother Tommy has eyes for cerebral Maura, whose own family life is complicated by her adoptive mother Constance and a biological dad with a link to the Mob.

Jane shot Maura's estranged father, crime boss Paddy Doyle, as he tried to defend Maura against an assailant - an incident which has driven a deep wedge between the two friends and colleagues. Jane and Maura will work hard to set aside their differences as they investigate a number of complex and troublesome crimes.

Jane and Maura will investigate a number of complex and troublesome cases, including the pending murder trial of Maura's biological father, Paddy Doyle. Plus, Lt. Detective Rafael Martinez, the newly appointed head of the Boston Police Department's drug unit, who has a conflicted professional past with Jane, will force her to relive a painful experience.