Touka and his classmates are abruptly catapulted into a fantasy world, summoned by the world's resident goddess to serve as heroes. The good news? Most of the students display amazing skills upon arrival! The bad? Mimori is the worst of the lot, bottoming out at a measly E-rank. Incensed, the goddess tosses him in a dungeon to die - but, it turns out, Mimori's skills aren't so much worthless as they are abnormal. Abnormally powerful, perhaps!