
Kidnapped during gym class, Mamori wakes up only to find herself stranded and under attack on the exotic island of Mermaid. As the residents of Mermaid are finally given the chance to return home to their families, Mirei and Mamori, along with Meifeng and Lady Lady, travel around the world in order to help others carrying with Armed Virus.Naïve 16-year-old Mamori Tokonome is accustomed to being teased at school for having an unfortunate surname that can also be read as "virgin." However, young Mamori will soon have to get used to being teased in other ways. With support from all of her friends, Mirei manages to defeat Momoka, removing the Armed Virus from her and everyone else. Combining together into a perfect form, the Valkyrie Drive, Mirei and Mamori battle against Momoka as she combines with allies to transform into a giant robot.

Inside the blade, as the captives are attacked by tentacles that draw the Armed Virus out of them, providing Momoka with enough power to even destroy a satellite, Mirei manages to break free and reunite with Mamori, freeing her from Momoka's control and releasing the others. However, Momoka uses Mamori's Valkyrie ability to absorb other girls into her arm and become stronger, overwhelming the others in a single shot and absorbing them.


Mirei struggles to fight against Momoka as she wields Mamori against her, but is aided by Kasumi, who is finally joined in battle by Hibiki, as well as Lady Lady and Meifeng.
