One day, Molly's dog Gus goes missing and the whole island community begin to search for him. Molly and her friend Bo hear a noise coming from the pirate cave and decide to follow it. As they head deeper and deeper into the cave, Molly and Bo finally find Gus. . . but the tide begins to rise. Will Molly, Bo and Gus be able to make their way out before the cave fills with water?
