Professor Vane is found dead at his desk inside a study locked and bolted from the inside. The family calls it a heart attack; the professor's last telegram to you called it murder, in advance. Examine the poisoned decanter, the unfinished letter, the burned card, the sealed windows and a dying man's hidden diagnosis; question the nephew, the niece and the housekeeper; and gather enough Evidence to name the truth before Inspector Hale's hour runs out. Ten verdicts wait — including one that explains why the only person in a locked room can still be the killer.