Synopsis: Jimi na Ojisan, Jitsu wa Eiyu Datta. -Jikaku ga Nai mama Muso Shitetara, Mei no Dungeon Haishin de Sarasareteta yo desu

Sato Keita (41 years old, single), a corporate slave salaryman who spends his days doing tedious work while feeling stressed, relieves his stress by sneaking into a "dungeon" that has appeared in the modern world and smashing through violent monsters as if it were a batting center! One day, his niece Hikari, who lives with him, secretly follows him and broadcasts the whole thing...!! ?