The boys have got a sinking feeling …A school trip to the remote island of Inis Fola might be Jack, Jerry and Yash’s idea of fun, but it sounds like hell on earth to Conan. And once the Doomsday Club boys arrive at Camp Eclipse, things get even worse: there’s girls and posh kids from another school to deal with. But then haunting blue lights are seen across the bog and people start to disappear.

Evil is stirring in the dark. Could the stories of a thousand-year-old demon buried beneath the bog be true? Maybe bringing the summonstone to a cursed island wasn't the brightest idea they've ever had …