Cambridge, 1933. On All Hallows' Eve, in a candlelit pew in ancient All Hallows Church, Doctor Adelaide Hartest witnesses a stranger's dying moments. Adelaide is just in time to hear his final confession: that he has plunged the dagger into his own chest, and that his death will be a suicide, despite its suspicious appearance. But his confession isn't enough to halt an investigation. The victim, it is revealed, is known to Scotland Yard, and his death...