Returning from Paris to discover a murder victim in her driveway, Boston medical examiner Maura Isles is shocked to discover that the victim looks exactly like her and is a twin sister she never knew.
FBI agent Gabriel Dean rushes into action to protect his pregnant wife, homicide detective Jane Rizzoli, when she is taken hostage along with others at the hospital by Nicholas Tennant, a black-ops agent in possession of high-level government secrets.