It's 1893 and thirteen-year-old Rory Mac, a poor, fatherless newsboy for Pulitzer's New York World, needs a break. He gets one when Hamilton "Ton" Fish, a member of the storied Fish family and star athlete at Columbia University, asks him to work his corner for an underground boxing match at McSorley's Alehouse, setting in motion an unexpected but inspiring friendship.

Ton gives Rory Mac someone to look up to and access to realms he could previously only dream of--New York's smart set, the power players on Newspaper Row, the Union League. In time, Rory helps Ton, who is big-hearted but whiskey-leaning, pick himself up after life knocks him down.

Their friendship carries both men West, to train in Texas, and then to the Spanish-American War, where they are confronted in dramatic fashion with the harsh realities and incredible possibilities that life can bring.

Alongside Hamilton tells the story of two unlikely friends who go to war for different reasons: Ton out of principle, Rory to rescue his first true love, the Cuban heroine Carmen Castilla. But they go together, and they go as members of Teddy Roosevelt's Rough Riders, the most uncommon lot of soldiers America has ever seen. In the process, they come to represent the magnificent potential of America itself.