WWEmma, Lee, Rick, and Chelsey are four 15-year-olds who love to scuba dive. their home is an idyllic island where centuries before pirates used as the base. some While diving on the Twizzle, Rick comes within millimeters of a 20ft shark. Emma is trapped underwater with a cannon on her arm and the shark out searching for his lunch. she is running out of oxygen. when Emma, Lee, Rick, and Chelsey take The Naughty Mayor to the mainland to collect the skipper, the come under attack from modern day pirates. The four teens go to explore Dead Mans Cave; what harm can they do? not a lot, but it takes the whole island to find them