Hilary Fenton, an American student at Cambridge, is overawed by the traditions and history of the University and instantly besotted with a fellow student Camilla Lathrop. He also befriends fellow student, Julius Baumann, who is murdered just after having asked Hilary to post an 'important' letter for him. Another murder follows and someone tries to poison Camilla. Hilary must try to establish what in the past could link the murders and who the murderer could possibly be.