Lucky Luke arrives in Nugget Gulch in the company of another lonesome rider, John "The Philanthropist" Smith. The town is buzzing with excitement over the coming horserace, and the considerable prize promised to the winner. Financially embarrassed, Luke signs up, counting on his exceptional mount to ensure victory. Unfortunately, Jolly Jumper is stolen just before the race! The lonesome cowboy will have to get by without his old friend back this time.