Jeremy Oakshott, Fellow of Jerusalem Hall and an authority on the Crusades, is content with life until renowned archaeolo­gist Mrs Lestrange urges him to join her expedition to Syria. His wealthy uncle, Ambrose Littlemore, refuses to help him, and is murdered soon afterwards. Detective Inspector Antrobus has already investigated the savage murder of one of Oakeshott's old friends, but the scholar's alibis are completely water-tight. Assisted by his doctor friend, Sophia Jex-Blake, Antrobus looks further afield, visiting two criminal lunatic asylums, a remote nunnery, and a quiet country village, where at last they uncover the truth about five savage murders, and the identity of their perpetrator.