There's excitement locally when Milo's town castle has been restored as a tourist attraction and will be ceremonially opened in two days. However, before the opening Milo's teacher, Miss Lee, doesn't turn up at school. Searching for Miss Lee, Milo and his bike are whooshed back through time to face bad cooking, draughty windows and Medieval thugs, braying for battle outside the walls of the castle. Can he manage to rescue Miss Lee from their clutches? It's up to Milo and his friends to put things right before the Grand Opening.