Haruna, a Magical Girl who fought evil to protect people's smiles, is suddenly transported to an unknown fantasy world by a mysterious magic circle. In this world, where 'Magical Girls' do not exist, the Demon King—once defeated by a legendary Hero—shows signs of resurrection, and hordes of demonic beasts plague the land. Upon learning that people's smiles are being stolen by evil here too, Haruna stands alone against a massive army of beasts threatening to destroy a village. No matter how battered or blood-stained she becomes, she never stops smiling as she eradicates the darkness. Slowly but surely, the name 'Magical Girl' begins to be carved into the history of this new world—.