Ali presses to open a cold file when a convicted murderer makes a dying confession to one less victim than he was sent to prison for. Nicco and Mickey look into a pair of homicide victims at a reform school.
The detectives tries to narrow the field in the search for the murderer of three students, while Ali tries to figure out her personal and professional life.
Ali investigates the death of a woman involved in the art scene who died of a drug overdose. Tensions mount when Christine embarrasses Mickey in front of the criminology class Mickey is teaching.
Len has a suspect delivered to him at an abandoned shelter in the forest in order to coerce a confession out of him. Ali and Mickey question a former teacher at Ambleton about the murder of two children there.
Mickey tries to convince Harper and Pawlachuk that a pile of old letters holds the key to a teen-aged girl's murder. Ali teams up with a Russian cop to connect stolen Russian historical documents to a murder.
Nicco risks his police career trying to save Billie from her pimp and from her addiction. Mickey and Ali wrap up the Ambleton case . . . or so they think.