The protagonist, Oomomo Ren, a 17-year-old who has dedicated his life to gaming and achieving maximum levels, finds himself in the deepest part of the "Vacuum Dungeon." After defeating five S-rank "Bloody Dragons" using his powerful dark magic, "Black Hole Zone," he finally achieves his long-held goal: reaching level 9999. This accomplishment unlocks an extra skill, "Instant Movement." Exhausted from a full day of grinding, Ren decides to return home to rest, lamenting his upcoming return to school due to the severe bullying he endures.
Ren's real-world life is a stark contrast to his dungeon prowess. He is a disheveled, socially awkward "game otaku" who is frequently bullied by his classmates, particularly Onizuka Aoi, who extorts money from him. Ren tolerates this treatment, finding it less troublesome than resisting, and his vast wealth accumulated from dungeon exploration makes the monetary loss insignificant. He overhears his classmates discussing popular dungeon streamers like Korius and Yuria, noting their success and the lucrative nature of dungeon streaming.
The next day, Ren returns to the Vacuum Dungeon to test his new "Instant Movement" skill. He hears a scream and senses three evil monsters nearby. Using his newfound ability, he teleports to the location and finds Yuria, a famous streamer with 10 million subscribers, being attacked by three "Death Devil Ogres." Ren effortlessly defeats the ogres with a single kick each, demonstrating the immense power of his maxed-out stats. Yuria, stunned by his power and speed, tries to learn his name, but Ren, wanting to avoid any complications, refuses and gives a false initial, "A.A." He dismisses the Death Devil Ogres' materials as worthless, further astonishing Yuria.
Ren's desire for anonymity is short-lived. The next morning, news spreads like wildfire about a mysterious, powerful explorer who saved Yuria, with some reports identifying him as a second-year student from Gotsuin High School. Ren, despite his efforts to conceal his identity, finds himself the subject of intense scrutiny and admiration from his schoolmates, who now view him with awe rather than contempt. This newfound attention is a source of great annoyance for Ren, who prefers the solitude of the dungeon.
Onizuka, jealous of the attention Ren is receiving, confronts him, disbelieving that the weak "kuzu" (trash) Ren could have possibly saved Yuria. He challenges Ren to a fight in the schoolyard, intending to publicly humiliate him and prove he's not the hero. Ren, seeing an opportunity to restore his former low-profile existence, willingly accepts the beating without resistance, aiming to re-establish his reputation as an incompetent individual. However, their fight is interrupted by the arrival of Yuria herself, who, having been streaming the encounter, confronts Onizuka for his bullying, much to Ren's exasperation.
