Fisher College at Cambridge lies between St. John's and Trinity College. Here one morning the bedmakers and gyps, clamouring for admission on the last day of term were admitted to find, lying across the path, the body of one of the College porters. The murder of the porter begins a mystery which deepens when it is found that the unpopular Dean of the college is missing. The search for the murderer is conducted in part by the police and partly by the Vice-President of Fisher College Sir Richard Cherrington, an eminent but slightly eccentric archaeologist with a penchant for amateur detection.