Still reeling from the death of one of their own, Ronnie and Joe face a new challenge when an innocent young mum is fatally stabbed in a busy marketplace, just as a senior police officer publicly pledges to crack down on knife crime. Under pressure from all sides, the pair struggle to gather evidence against the youth they think is responsible, and the suspect's unintentional confession appears to bring the case to a close. However, Ronnie is the only person who hears the admission, and it proves difficult getting anyone to believe him. With the detective's honesty cast into doubt and his effectiveness questioned at every turn, is this the end of his career?