The TARDIS is dragged down a time corridor, forcing the Doctor, Tegan and Turlough to materialize in a disused part of London in 1984. The corridor links Earth with a battle cruiser in the future that contains the Doctor's oldest enemy - the Daleks. Having lost the war with the Movellans, only one person can now help the evil race. With shocking consequences for the Doctor, it is time for the Daleks to resurrect their creator Davros.