Sam Cooper had just moved to Harper's Inlet when he met Tony. Tony's father owned a marina. Sam, Tony, and Tyler took scuba lessons together. Tony got them in for free. After they completed the course, the boys decided to try out their new skills in the real world...the ocean. The only problem was, no one had permission. While Tony's father was away on a buying trip, the boys took one of the rental sailboats out for their diving adventure. Everything went well until the biggest storm Tony had ever seen blew up from out of nowhere, and the boys found themselves stranded on Lost Island. But, if they thought the worst had happened, they were wrong. The boys discovered a secret hideout that was used by men in high powered speedboats. Sam and his friends knew the men were up to something, only they didn't know what. They had to find a way to stop them, but how? And, even if they did, the boys could never tell anyone about it. Join Sam Cooper, Tony, and Tyler on their scary scuba, ocean, island adventure