At the end of Compass South, twins Cleo and Alex were been reunited with their father, Mr. Dodge, on the ship Anita after a battle with the pirate Worley. Now, Cleo explains to Dodge and Alex that the pocket knife and pocket watch they have are keys to a treasure. So begins Knife's Edge, the second installment in Hope Larson's Four Points series another high-speed story of treasure, family, and of course adventure on the high seas.