Following the events of Zero no Tsukaima: Princesses no Rondo, Saito Hiraga and Louise Françoise Le Blanc de La Vallière take the offensive. Together, with the aid of two "void" power wielders, they confront King Joseph in Romalia's Holy City. However, as they prepare for battle, an ancient evil lurks in the shadows. As they face numerous challenges, will their close relationship prosper or crumble under the strain? Zero no Tsukaima F chronicles the final trials Louise and Saito must endure as they confront their fate together.