Touru has scored a super-cheap cheap apartment in Tachikawa, Tokyo -- because its front door opens into a classic fantasy dungeon. But the number of roommates keeps increasing. Now a rare white slime and a sexy elf have moved in!! As the first human to ever level up, Touru is planning a safer and easier way to grind more levels by breeding monsters, then defeating them remotely! But things get real as Touru ventures into the dungeon and saves a mage from a fiendish beast!