Northwest Passage

"Twenty years after fighting the French in the French and Indian War", is stated above in another comment, as when someone returned to fight for the British in the Revolutionary War.

Considering that the French and Indian War was in 1763, twenty years after that was 1783, which was the year that the Treaty of Paris was signed between Great Britain and the United States, which fully- recognized the independence of the United States! The Revolutionary War was long over with by then, ever since Cornwallis had surrendered to George Washington and his army at Yorktown in October 1781.

Hence, that "twenty years" is way off. Fifteen years would give 1778, which was in the heart of the Revolutionary War.