A series of murders of young women has the police commissioner pressing detectives for answers. The victims all left clubs with names following a pattern - P, L, A, Y - and the crimes occurred at 3 am. However, an elderly waterman reveals another crucial link: the dates all coincided with high tide on the River Thames.
Murder at 3am
A detective's investigation into a string of murders takes a personal turn when he becomes convinced that his sister's partner is the culprit.