Following a vice squad celebration, P.C. Curles knocks over a young boy; chased by Supt. Cullen, a traffic officer, he evades him, changes back into his uniform and returns to the scene, pretending to assist. The car he was driving turns out to be unregistered and, finding only a blank police memo pad in it, Maureen has little to go on. The boy's parents complain and Clark is called in to investigate. The hit and run victim dies, and Clark discovers an ongoing feud between traffic police and the vice squad; evidence of the accident initially points to the wrong officer, but eventually Curles is interviewed. However, since he assisted at the scene, his fingerprints are all over the car.