Satoru is a poor young man. He is supposed to enjoy Christmas with his only living relative, his younger sister, but suddenly finds himself in a different world where magic exists. The man is summoned by Leia, a beautiful girl who calls herself the "Immortal King". Although she has summoned Satoru with the results of hundreds of years of work, she has no way to return him… By some mistake, Satoru has a huge amount of magic power that is impossible to find in the world. Leia surrendered before Satoru. Satoru’s journey begins in order to return to his world.