A love of Arthur Ransome's books brings two youngsters together in a project to rebuild a dinghy, in this modern day Swallows and Amazons style adventure.A simple map hidden in the bottom of an old sailor's trunk leads to a set of clues and small rewards, but with each new riddle they solve, they find a better treasure.From a south coast estuary to the northern hills, the quest becomes a race to outwit the greed of a present-day pirate, and solve the Mystery of the Lake.Even with the help of their older siblings, their innocent adventure goes horribly wrong as they fall foul of a group of desperate criminals.The boys become the hunted, and the race for the treasure turns into a flight for their lives.