Young graduate student Jane Chase becomes the new assistant to an eccentric zoology professor at the remote home he shares with two brilliant chimpanzees and an elderly orangutan butler named Link. But when one of the chimps is found dead and the professor mysteriously disappears, Link becomes dangerously aggressive towards Jane. Now, the time for “monkey business” is over and the true terror is about to begin.
American heiress Henrietta Doran (known as Hatty) marries Lord St Simon, but she vanishes without trace on her wedding day, leaving London agog. Later, the police find her wedding dress in the Serpentine, a lake in a London park, with a note in the pocket of the dress. While investigating the case, Holmes suffers from nightmares, which he sees as a factor in the mystery.