Class 2-C's bus is enveloped in light, and the Goddess, Vicius, summons the students and their teacher; she hopes to raise them as Heroes to defeat the Great Demon Empire, and she welcomes the students; however, Mimori Touka is branded a trash hero.

Touka rediscovers his cruelty as he kills monsters in the Ruins of Disposal; he means to escape and exact his revenge on the Goddess Vicius, but to get there, he'll have to face the grotesque monster that's killed so many before him, the Soul Eater.

Armed with experience and a book of forbidden magic, Touka sets out on a journey for revenge; before he can get far, he encounters a beautiful woman fleeing a group of four men known as the Holy Watchers.

Touka arrives in a new city and decides to try his hand at the local ruins in hopes of scavenging material for a special potion to enhance his pet slime.

Touka asks Seras to guard him on his way to the Land of Golden-Eyed Monsters; they agree to meet after the reward ceremony for conquering the ruins, but Seras doesn't show even long afte the appointed time.