 Hazel Wallace returns from her training as the new Detective Sergeant. Supt. Mullett assigns her to sorting the mess left behind by DI Frost while he was on extended compassionate leave. Wallace s first case is a man found hanged in his home. She suspects the death was not suicide. A set of fingerprints at the scene belong to an unidentified man discovered drowned a year previously. Frost is summoned by Supt Mullett to sort things. He connects a painting that appears to have been stolen from the hanged man with an art robbery and murder several years earlier.