A rough treasure map, discovered in a neglected dinghy, starts two boys on a set of clues, each one bringing a greater reward. It's not plain sailing (as they say), because all the way, they are dogged by a modern day pirate, who wants the treasure for himself. They think they have escaped him when they travel north to the remotest part of the Lake District, but then fall foul of a gang of desperate criminals. While their family is besieged, the boys make a break for it in their dinghy. Will they ever find the treasure, or simply be lucky enough to escape with their lives? Swallows and Amazons for the 21st century.