When the bursar of Lichfield College is found strangled in an Oxford hotel, Detective Chief Inspector Jonah Porter rapidly concludes that the killer is one of the nine college staff attending a meeting there, but who is the most likely suspect? Is it mathematics fellow, Tom Carrington, who found the body? Or was it the Master, who was the last to see him alive? Was the bursar blackmailing one of his colleagues? Or could it be a crime of passion committed by his former mistress?