After defeating the Demon King, Yuuki, a hero who saved another world, finally returns to Japan, only to find that “dungeons” have appeared all across the globe. These dungeons, in addition to being filled with vast treasures and rare items, are infested by fierce monsters. At the same time the dungeons appear, “skills” awaken within the bodies of people on Earth, who are given the name "Hunters." Our protagonist, after returning from the other world, takes the Hunter exam and, after having obtained the “Carrier” skill, he registers as a low-ranked Hunter. Thus, Yuuki sets out to conquer the dungeons, making full use of the large number of items he brought back from the other world.