Six-year-old Josef is tormented by bullies. He is rescued from his misery by an older boy, Mosche, who lives in the Jewish quarter of Worms, a city on the Rhein River. The two boys and Mosche's sister Miriam become friends, spending time together as Mosche teaches Josef to read. Miriam herself learns eagerly, though few of her eleventh-century contemporaries think it desirable to educate girls.
The boys are excited to meet the beloved Rabbi Scholomo of Troyes. He is called "the rabbi of Worms" by the local Jews since he once studied and taught in their city.
Josef and Mosche maintain their friendship, even as "citizen armies" of Christians inflict violence on Jews during the early days of the First Crusade. In a dangerous and chaotic time, Rabbi Scholomo's teachings provide help and solace to those who face horrible dilemmas.