A 1970s boy organizes the Children's Crusade
Rudolf 'Dolf' Hefting, a boy from the twentieth century, is thrown back by a failed time-machine experiment to 1212 and joins Nicholas of Cologne's crusade of thousands of children marching toward Genoa to free Jerusalem. Using ordinary modern knowledge, he splits the chaotic mass into units with chosen leaders, sets up rationing and scouting, and enforces basic hygiene so that far more of them survive the Alpine crossing. When the promised miracle fails and the sea does not part, the survivors face abandonment and adults who plan to exploit them.