A Man in His Late 30s Living in the Tokyo Dungeon

The world, devastated by the sudden appearance of dungeons, is now slowly recovering. One day, a dungeon appears right in the home of Niwa, a single, middle-aged man in his 30s. When he manages to defeat the monsters lurking inside, he levels up and gains special skills. Armed with these new skills, he sets his sights on turning his lackluster life around!