In 1814, pirate Jean Lafitte (Fredric March) controls the bayous separating the gulf from the ocean, and is wanted by the Louisiana governor. Although the British naval forces attempt to bribe Lafitte to help them attack New Orleans and Gen. Andrew Jackson, Lafitte feels a sense of obligation to America, despite attempts by the corrupt Senator Crawford to portray him as a liar. After he's attacked by a former officer of Napoleon's forces, Lafitte decides to aid Jackson's defense of the city.