With only the British Channel dividing the antagonists, Napoleon's war with England has come even closer to Portsmouth by 1804. The threat of French invasion looms large, and with it the danger of sabotage at factories, ropewalks, and naval stores in busy, scruffy Portsmouth. When an enigmatic French prisoner of war escapes a prison hulk in Portsmouth harbor, Able Six and the Gunwharf Rats must make certain disaster doesn't strike too close to home, and all they hold dear. Whatever the cost, the unlikely master genius will protect his beloved Meridee and their infant son, or die in the attempt.