Ten years have passed since four boys and girls were summoned from another world and defeated the Demon King.

Arsal, a former hero who saved the kingdom and now serves in the royal army, finds himself falsely accused of a crime he didn't commit. The king, blinded by peacetime complacency, ignores Arsal's calm reasoning and mocks him as a useless burden, completely forgetting his heroic deeds. Fed up with such foolishness, Arsal abandons the kingdom, grabs his severance pay, and sets off on a carefree journey to enjoy a slow life. However, his overwhelming power makes the world see him as a dangerous threat aiming for world domination!?

"Fine then — extinction it is."