In a world where dungeons are a normal part of everyday life, a young man named Touma spends his free time lurking on message boards, live-commentating on dungeon activities from the sidelines. While exploring an A-rank dungeon, he stumbles upon a violent scene: a female streamer named Yukihana has been impaled by a group of minotaurs. Acting on instinct, Touma single-handedly defeats the monsters and revives her with an ultra-rare potion, all while remaining completely unaware that her drone is broadcasting the entire rescue live. The footage explodes across the internet, and Touma inadvertently becomes a viral sensation.

Forced into the role of a video streamer, Touma continues to explore high-level dungeons with a calm, detached demeanor that belies his overwhelming strength. His on-screen exploits attract a loyal audience and the attention of other adventurers, though he himself shows little interest in fame. As his reputation grows, a colorful cast of characters gathers around him, including members of a behind-the-scenes forum who support him from the shadows. The story follows his accidental rise as a streaming star while he takes on increasingly dangerous dungeons, eventually setting his sights on the legendary dungeon known as Babel. Along the way, fragments of Touma’s hidden past begin to surface, hinting at the reasons behind his exceptional abilities.