Yuko Murikami stops by a shrine to pray for the new school year. Yuko accidentally breaks the bell and drops it on top of a turtle's head. Because she is the only person that stopped by the shrine in a long time, he grants her the power to become a superheroine, based on another ancient deity. It is her job to protect her neighborhood from the threats it faces. By yelling "Cosmo Magic! Métamorphose!!", she transforms into the Masked Beaty Poitrine!.