The Plain Salary Man Turned Out to Be a Hero: He Was Invincible, Only to Be Exposed on His Niece's Dungeon StreamJimi na Ojisan, Jitsu wa Eiyu Datta. ~Jikaku ga Nai mama Muso Shitetara, Mei no Dungeon Haishin de Sarasareteta yo desu~

Keita Sato, a 41-year-old single office worker, spends his days handling stress and tedious work tasks. His unique way of unwinding involves diving solo into modern-day dungeons and using ferocious monsters as batting practice! One day, his niece Hikari secretly follows him and ends up streaming his dungeon exploits...!!