It happened to be in the modern era when humanity became subjected to the menaces of the dragons. To fend for themselves, people conjured ways of manipulating magic to summon and impel manufactured, so-called "Leviathans." The contractors of these "serpents" were supposedly the only ones designated to destroy the dragons, as they were the world's valkyries of salvation. Named "Magi", these maidens would accompany their leviathans as they were meant to lead the everyday resistance against the dragons...

This is an adaptation from the light novel series written by Taketsuki Jou and illustrated by Nimura Yuuji.