— A bomb in the mail
— Poisoned chocolates
— A locked-room knifing
— A weirdly disguised killer

A deadly net of danger tightened around Hilary Foulkes as an unseen enemy made constant, bizarre attempts on his life. Detective Terry Marshall and his unusual assistant, the inquisitive nun, Sister Ursula, worked desperately agains the clock to break the case—for Foulkes’s luck was due to run out any second!