Professor Coke Norris is killed in a hit and run. At the same time Thursday is perturbed to learn that the new owner of the Moonlight Room night club is Vic Kasper,a London gangster with whom he has history. Morse finds proof that Coke Norris visited the club as well as discovering that he was opposed to the sale of college land to build a housing estate. The murder of a cigarette girl from the club used in a blackmail plot to expedite the sale leads Thursday to Kasper as Morse discovers the reason for his superior's hatred of the man and they combine to act when Thursday's daughter is endangered. Morse then works out the real reason for the professor's murder before sitting his sergeant's exams.