The first day of Paddy's trail ends prematurely when a key witness is killed in a car crash. Maura learns more about Hope and Paddy, despite Hope's unwillingness to talk about the past.
Jane and Maura are asked to speak about Hoyt at a seminar on serial killers for law enforcement. However, the scene they are are to use to demonstrate investigative technique is rather more real than expected.
Two puzzling murders share a surprising link that could be the key to finding the perpetrators. Meanwhile, Jane and Casey come to a crossroad; and Maura becomes the caretaker for Patrick Doyle Sr. when he's released from prison.
The Boston Police department is haunted from the past when a man in a clown costume almost kidnaps a little boy. Is it the same person that has molested and kidnapped boys in the 1980s?
