In the near future—Earth is under invasion from interdimensional monsters known as "False Beasts," and forced into an endless defensive war.

Conventional weaponry is largely ineffective; the only countermeasure is the powered suits known as "Valkyrie Dress," which can only be piloted by women possessing mysterious powers.

A man is assigned to the "Third Academy," an institution that fosters and manages these women who don and fight in such steel dresses.

His name is [Hifumi Ren].

He was a test pilot for an anti-False Beast humanoid weapon—a project whose experiments had never once succeeded.