When the young heiress Norma Restarick tells Hercule Poirot that she may have killed someone, it seems she’s telling the truth--her childhood nanny is soon found dead and those close to Norma fear for her sanity. With crime novelist Ariadne Oliver, Poirot uncovers a conspiracy rooted in a tragic family history and finally has to take life and death into his own hands to reveal the shocking truth.