In January 1927, Agatha Christie is on an ocean liner bound for the Canary Islands. She has been sent there by the British Secret Intelligence Service to investigate the death of an agent, whose partly mummified body has been found in a cave.

Early one morning, Agatha witnesses a woman fall from the ship into the sea. At first, nobody connects the murder of the young man on Tenerife with the suicide of a mentally unstable heiress. Yet, soon after she checks into the glamorous Taoro Hotel, Agatha uncovers a series of dark secrets . . .