After Ezoe Kazuhiko, a middle-aged managing consultant, triggers the Dungeon Outbreak Phenomenon, the world is suddenly plunged into chaos. Now at the head of the very first adventurer guild, Dungeon Busters, Ezoe is determined to do everything in his power to protect the world from the bleak fate that awaits if the dungeons aren't cleared within ten years. As the different world powers finish organizing themselves to face the threat of dungeons and deploying their forces, a mysterious man dwells in the darkness, taking upon himself a very different mission... How will the newly formed Catholic military force, the Crusaders, who have just arrived in Japan, and the new members of Dungeon Busters, led by Ezoe, handle the tremendous task of clearing dungeons? Follow the fate of the world as humankind retaliates in the third volume of this dungeon-delving epic with overwhelming realism!