When Tom's adversary Ria steals an old boot from King Hugo's palace it turns out she has a shocking plan. She uses a powerful magic stone circle to travel back in time, planning to stop Tom's ancestor Tanner from succeeding in his battle against Petorix the Winged Slicer. If she manages to change the course of history, Tom himself will never have been born! Tom and Elenna must follow Ria into the past, defeat Petorix and save Tanner before Tom himself vanishes completely.