Poor heartbroken Jane. After Casey, the love of her life, broke up with her, she's depressed and losing weight. Maura and Angela try their best to help her snap out of it, but Jane's grief runs too deep. And now there's a bizarre new murder to investigate: Victoria Green, 25, killed with a blunt object and posed on a bus stop bench. Her face has been lovingly made up like an old-fashioned doll, and she's dressed in ‘90s clothes, details that suggest the killer is a freak with a doll fetish. Could it be Herb Buckley, recently released from prison, who dressed up prostitutes as dolls? Or is it Victoria's married boss, with whom she was having an affair?
As Boston PD chases down clues, Korsak finds a new friend: a lovable lost dog (with a debut performance by Elsie, Lorraine Bracco's real-life pet). The dog has an embedded RFID chip that tells Maura she belongs to a nearby veterans' center – the same center where Casey works. When Maura returns the dog, she's stunned to discover that Casey is partially paralyzed, a secret he wants Jane never to learn. Burdened by this secret, knowing how much Jane is suffering because of the break-up with Casey, Maura finally spills the beans to Angela – with predictably disastrous results.
Meanwhile, two other doll victims have turned up. All of them were killed by the same weapon – a wooden club that still bears decades-old bloodstains. Was the killer already at work 20 years ago? Where has he been since? To solve the riddle of the dolls, Jane and her team must dig into the past to find a man who's gotten away with murder for far too long.