One fateful day, a caravan was passing by the village of Teira, which had been raided and set ablaze by bandits. Within the burning rubble, a young woman found a baby, the sole survivor of the attack, and decided to take it with her and raise it as her own. As she was leaving with the little child in her hands, two falling stars lit up the night sky, and she named the boy Asterios.

Years passed and the boy grew up in a caring and warm home, developing a passion for all magical beasts, choosing the path of a Summoner as his way of life. While his love and knowledge also grew boundless, his practical abilities clearly pointed out his complete lack of compatibility with that school of magic, but he never wavered in his resolution.

Follow Asterios as his life of perpetual failure suddenly takes an unexpected turn, after just seconds short of his death, a powerful summon answers his call and saves his life. Wait... doesn't it look like... A GIRL?! Are those beast ears and tail?!