David Blake and his sister Sally have grown up with the legend of the Blake treasure, buried on one of the islands off Saturday Cove, a fishing village on the coast of Maine. One day, while lobstering in the bay, David and Sally seek shelter from a summer storm in an abandoned house on Blake's Island. There they find a musty chart that seems to be a definite clue. Curious and excited, they decide to solve the family mystery.<P> But Sally loses the chart, and David reckons without the...