Sato is a high school boy in love with his best friend Hime, an unearthly beauty from another realm. So when she moves back to her home world to get married, Sato doesn’t think twice—he follows her and crashes the wedding. Then, after a kiss from Hime, he suddenly becomes the new groom! But here, Hime is a Ring Princess and her husband is destined to be the Ring King: a hero of immense power.

The hero Toto has talent, but his shyness has prevented him from forming a party. As he languishes in the town of origins, three beautiful women—Ciel, Anemone, and Goa—invite Toto to join their party out of the blue. Toto gears up to begin the journey, but unbeknownst to him, all three women are plotting to kill him for their own reasons!

Fourteen warriors set out to prevent an invasion, but only seven return. Three died along the way, and four were slain for betraying the empire. In truth, it is the Seven Heroes who turned on their allies so they could take all the glory. Ascheriit was their victim, but now, 20 years later, he is back to get revenge.

When the Pillars suddenly appear on Earth, threatening all life, it's only the act of the god Odin that offers humanity salvation. Providing a means of fighting back, he gives Earth the Valkyries, young female pilots with supernatural powers and spirit fighter planes. These skilled troublemakers, all young, risk their lives in a long-running war—but the final battle is fast approaching!