In the near future, Earth has been invaded by monsters from another world called giju, forcing humanity into a never-ending war for survival. Conventional weapons are ineffective; the world’s only hope lies in the Valkyrie Dress—suits of powered battle armor with extraordinary combat abilities that can only be piloted by women. However, one day, a man is transferred to the Third Academy, where the ladies who wear these dresses of hardened steel are trained. His name: Ren Hifumi, the test pilot for a prototype humanoid weapon created to combat the giju that has never had a successful trial run…until now.