Young Timothy Malt and his dog, Grk, are vacationing in an island paradise. Unfortunately Tim has a cold and is stuck inside the hotel while everyone else goes scuba diving and enjoying the islands. When Tim finally feels better, he goes out for a walk on the beach and stumbles upon a body washing up on shore. It's the body of a man who gasps his last words to Tim, 'Help them.' Tim runs for the police and eventually gets help, but the man dies. Now, Tim is a courageous chap and, when he figures out that the dying man's last word to him was 'Calypso' and that Calypso is the name of an island in the area, he gets curious. His curiosity leads him to steal a boat from his parents and crash it onto the shore of a heavily guarded private island. He awakens from the accident and finds himself in a hail of bullets. He has intruded into the space of a heavily-guarded, private island. Action and adventure and a bit of a lesson in science await.