War comes to the island of Cuba and when the United States fights with Spain over the possession of the island, Casca opts to join the US Army as a cavalryman. Without their horses, they become known as the 'Rough Riders', and under the charismatic command of Theodore Roosevelt, take part in the legendary charge up Kettle Hill outside the city of Santiago.
But Casca is not only fighting the Spanish in Cuba; he also becomes mixed up in a quarrel between a young Spanish woman and the Cuban irregular who forces his attention upon her, and Casca's sense of nobility is such that he cannot sit by and allow this act of violation to go unpunished.