When Don and Jim Mercer and their buddy Terry Mackson set out in their sloop, Lassie, for a visit to Mystery Island, they were in search of adventure and fun. But they quickly found they were getting more than they bargained for -- real danger, a skirmish with marine bandits, and a fight for their lives. This is a thrilling adventure story of three modern boys -- with action and excitement on every page. [Volume 2 of The Mercer Boys.]