Rosina Zambelli is placed in an Italian convent as her parents leave Italy for America, promising to bring her over once they are settled. Two years later, when Rosina is 13, they send for her to join them just outside Boston. By this point, she has turned away from the strictures of religion. Ensconced in her parents' railroad flat, she begins working in a garment factory and enrolls in an English class. It is there that she meets Nicola Sacco and his younger brother Ferdinando, who is a gentle, thoughtful soul apprenticing as a shoemaker and harboring a passion for equal rights for poor laborers. Ferdinando and Rosina fall in love and become engaged. But when Nicola is murdered, a distraught Ferdinando takes his brother's name, becoming Nicola Sacco.

By 1913, they are both active members of the burgeoning Italian Anarchist movement, distributing pamphlets, attending meetings, and protesting the mistreatment of sweatshop workers. Along the way, Nicola becomes friends with pacifist, philosopher, and poet Bartolomeo Vanzetti. Anti-Italian bigotry increases with the advent of World War I, and though Nicola and Rosina are pacifists, the Anarchist movement itself becomes violent. Nicola and Bartolomeo are later arrested and convicted for a murder. Their supporters, including Rosina, believe they have been framed and wrongfully convicted. Will the love and support be enough to save their lives?