Ichiro Yamada and fellow studentRyugin were summoned to another world on their way to the opening ceremony of the school year.With Ryuguin the hero and Yamada the Holy Knight, they decided to conquer the Twelve Labyrinths. All in order to save the world, and to obtain an item that will allow them to return to their original world!Having gained the status of a hero, Ryuguin plays around without making any effort. On the other hand, Yamada, who wanted to return to the original world, worked hard to conquer the labyrinth while being battered and bruised."The one who supported me was supposed to be the heroine of the same party...!"This is the story of a holy knight who has lost all the girls he has fallen in love with to the heroes, and who runs away from his party to find the love of his life.