Two months after the events of A Talent for Murder, during which Agatha Christie "disappeared," the famed mystery writer's remarkable talent for detection has captured the attention of British Special Agent Davison.

Now, at his behest, she is traveling to the beautiful Canary Islands to investigate the strange and gruesome death of Douglas Greene, an agent of the British Secret Intelligence Service. As she embarks on a glamorous cruise ship to her destination, she suddenly hears a scream. Rushing over to the stern of the liner, she witnesses a woman fling herself over the side of the ship to her death.

After this shocking experience, she makes it to the Grand Hotel in a lush valley on the islands. There, she meets a diverse and fascinating cast of characters, including two men who are suspected to be involved in the murder of Douglas Greene: an occultist similar to Aleister Crowley; and the secretary to a prominent scholar, who may also be a Communist spy. But Agatha soon realizes that nothing is what it seems here and she is surprised to learn that the apparent suicide of the young woman on the ocean liner is related to the murder of Douglas Greene. Now she has to unmask a different kind of evil in this sinister and thrilling mystery.