Frank and Ali reopen the case of Leonard Larkin, whose son was acquitted of his murder and now claims his sister killed their father, and that her husband gave her a false alibi. Mickey's case is referred to Homicide.
Ali and Mickey reopen a 12 year old case, which was originally judged a murder-suicide, based on the word of an arrested drug dealer. After a man reports being attacked by a dog, Frank investigates whether the dog-owner earlier had killed his wife by ordering the dog to attack her.
Frank gets personally involved in a seven year old case when a man comes to collect the personal effects of his father, who was awarded the Victoria Cross for his heroism during the Normandy Invasion in 1944.
The investigation into a prison inmate's killing by a guard who was under the care of a high-profile self-help counselor is complicated by the fact that Mickey is also a client of the counselor. Christine's brother is brought in on a petty beef, and she arranges his release.
Ali and Mickey are called to the scene when a mutilated body is discovered by a man driving his SUV off-road. Sam later identifies the body as a man Dean Bulmer was convicted of killing on the basis of another body Sam mistakenly identified.