Newly orphaned Anne Beddingfeld is a nice English girl looking for a bit of adventure in London, but she stumbles upon more than she bargained for. Anne is on the platform at Hyde Park Corner tube station when a man falls onto the live track and dies instantly. A doctor examines him, pronounces him dead, and leaves, dropping a note as he goes. Anne picks up the note, which reads "17.1 22 Kilmorden Castle." The next day the newspapers report that a beautiful ballet dancer has been found dead there—brutally strangled. A fabulous fortune in diamonds has vanished. Aboard the luxury liner Kilmorden Castle, mysterious strangers pillage her cabin and try to strangle her. What are they looking for, and why should they want her dead? Lovely Anne may seem the last person on earth suited to solve this mystery—and yet she is the only one who can. Her journey to unravel the truth takes her as far afield as Africa, the tension mounting with every step as she struggles to unmask a faceless killer known only as "The Colonel."