Steve Perry's mother was a widow with a slight chance of inheriting a goodly sum upon the death of her uncle. However when David Martin died there seemed to be nothing left except a mysterious chart. David's friend Saito acted very queerly about a copy which he made, but the boy did get real help from a man called Peter Barr. The chart led to the discovery of the gold mine on a small Aleutian Island from which the uncle's untold wealth had come. Steve's path was crossed by the Japs at every turn but at the very end, though they had to blow up the mine, our enemies lost a sub because of the decision of the boy.