When two newlyweds move into their new home, only to discover that a corpse has been buried in their basement a few months prior, a gruelling case is begun to trace the identity of the victim. With all avenues of investigation approaching exhaustion, a tenuous lead offers a chance for Chief Inspector Moresby and leads him to the amateur criminologist Roger Sheringham, who has recently been providing cover work in a school south of London. Desperate for evidence of any kind on the basement case, Moresby begins to sift through the manuscript of a satirical novel Sheringham had been writing about his colleagues at the school, convinced that amongst the cast of teachers hides the victim - and perhaps their murderer.