Murder at an English boys' prep school: unpopular headmaster Henry Carter is found, stabbed, in the school pool. Enter, then, Scotland Yard's tall, lanky Inspector Barnaby--and there's no shortage of suspects for him. Carter was about to publish a monograph on English history which duplicated the life's work of teacher Dennis Jordon. He was blackmailing a school matron (with a rich, prim aunt) who was having an affair with a seedy teacher. He enraged the staff with his lax, inconsistent policies. And, in Agatha Christie style (a rather pale imitation), it's revealed that Carter had an enemy from his WW II past--an enemy who happens to be on the school staff. Very routine materials--also a second murder and some fiddling with alibis--but Shaw writes with enough pleasant, literate assurance (mildly comic, mildly serious) to make this a serviceable item for English-mystery traditionalists.