In the end of the sub-seventeen soccer game between Holland and Belgium, the selfish teenager Rudolf "Dolf" Vega does not assist another player and loses the goal and the classification of the Durch team. He feels bad and when he meets his mother Mary Vega, who is researching a prototype time machine, in the laboratory, he decides to return in time to fix the game. He steals the access card of his mother and during the night, he breaks in the laboratory. However, he does not fit the correct date in the display and he is sent to 1212. He is attacked by marauders but he is saved by the young Jenne, who is skilled in sling and is traveling through the forest to join The Children's Cuzade to Jerusalem. Dolf puts a milestone on the spot and follows Jenne and her friends. Sooner they join the Cruzade that is led by Father Anselmus and a group of young noblemen. Dolf names himself Rudolf, the Duke of Rotterdam, and is assigned to take care of the children. When Dolf misses the chance to return home and is stranded in the Thirteenth Century, he follows the Cruzade and discovers the treacherous plan of Anselmus of selling the children to slave traders. But how can he convince the children that their charismatic leader is a traitor?
