Sim and Nadir investigate when a man is found beaten and unconscious in a skip on a deserted industrial estate. With no apparent motive for the attack, it isn't until a friend of Fletcher's who owns a local boxing gym gives him some information on an illegal bare-knuckle fighting operation that the team finally discover who may have been responsible. Meanwhile, Hardy and Keane take the lead on a case of criminal damage involving a forty-something singleton and his estranged mother - only for the case to take a surprising turn when the man confesses to murdering his own wife during the interview. However, with no evidence to prove his guilt, the pair are forced to let the man go.