Near the end of the Showa era in the late 1980s, in Misaki town, an old mansion is rumored to be the home of a witch. After moving into the mansion, Aoko Aozaki begins to learn sorcery from a young mage, Alice Kuonji, the rumored witch of the mansion. The Aozaki family oversees the land on which Misaki is built and the heir (Aoko) is tasked with protecting it. Mysterious intruders have been disrupting the bounded field in Misaki, leading Alice and Aoko to investigate. A mannequin or puppet attacks them and is incinerated. As this happens, both of them spot someone running away, a civilian who must not get away having seen magic alive. Unexpectedly, a young boy named Soujuurou Shizuki is drawn to the mansion and comes to reside with them as well.

Hajime Nagumo and his high school class are suddenly summoned to a fantastical land as heroes. But while most of his classmates have powerful stats and abilities, Hajime does not. Underappreciated and unprepared, he tumbles into the depths of a monster-infested dungeon where voracity and sacrifice are his only options. To thrive in this savage world, he’ll have no choice but to welcome the abyss.