Three years have passed since dungeons first appeared. In a world where dungeons have become a pervasive part of daily life, 25-year-old Akira Akatsuki, whose contract at his temp job was recently terminated, found himself unemployed and unable to reap any of the dungeons' benefits.

With 'third time's the charm,' Akira finally obtains the qualifications to delve into a dungeon, and risking everything for a single chance to turn his life around, he plunges in.

However, the skill he acquired was what's known as a 'dud skill'—