Newly promoted to Detective Chief Inspector, Carol investigates a murder which seems to bear the hallmark of gang boss Gavin Cochran. However Cochran is behind bars for murder and could not have done it. Carol asks Tony to work out any links between the two slayings, leading to the arrest of Cochran's brother George. But there is a fight during which George ends up in a coma. Gavin is released from prison for a compassionate visit, during which another killing takes place, allowing Tony to test his theory and trap the murderer.