PC Dave Quinnan returns to duty, and is determined to prove to everyone that he's back to normal after his breakdown. Out in a panda car, Quinnan sees a man shot in the head in a van - he calls for assistance, but by the time reinforcements arrive, the victim, the van and the main witness have disappeared. Desperate to prove his sanity, Quinnan pursues the case vigourously, and enlists the help of DC Paul Riley's brother Joe, who asks the wrong people the wrong questions. PC Polly Page is outraged by a practical joke played by PC Taviner, but she and Quinnan get their revenge in a most amusing way.