A celebrated speedrunner known online as Shachiku Taitei, the reigning champion of the action RPG Another Verse, falls asleep during a practice session. He awakens to find the game's familiar opening sequence playing out in perfect detail around him. Finding his body moves even more precisely than in the real world, he immediately defaults to his singular goal: clearing the game as fast as possible. He ignores the ceremony where Queen Eida of the Kingdom of Truelli tries to offer him the legendary Holy Sword to defeat the Demon King Apocalypse, instead using a wall-jump to escape the throne room. He bypasses the Adventurer's Guild tutorial, fights through the Forest of the Undead stripped to his underwear to exploit the game's dynamic difficulty, clips through walls to skip mid-boss fights, and defeats the Demon King with a glitched wooden stick. Only after this perfect run does he realize this is not a dream. To his horror, his speedrun has caused a critical problem. By defeating the Demon King so quickly in the prologue, the game has locked into its hardest difficulty setting. Worse, Queen Eida, the Saintess of Salvation, has been transformed into her cat-eared alter-ego Daanya and cannot access her magic. Without her power, she cannot seal the "roots of evil" that spawn monsters, nor can she send the hero home. To fix the broken game state and unlock the true ending that might allow his return, Shachiku must now defeat the Demon King's Elite Four lieutenants.

The main character is Shachiku, a hyper-fixated speedrunner whose knowledge of glitches, clipping exploits, and game mechanics is encyclopedic. He treats his predicament like a broken run to be salvaged, maintaining a deadpan demeanor while narrating his actions as if to a streaming audience. Daanya is his companion, the powerless queen whose common sense is constantly assaulted by his bizarre logic. The main antagonists are the Elite Four, whose difficulty has been scaled up due to the Demon King's premature defeat. They include Raspi, who is defeated by a lag glitch that disables collision detection, and Arachne, whose near-invulnerability is bypassed when Shachiku exploits a coin-throwing technique that deals scratch damage without counting as an attack. Other notable figures include Kiira, the guildmaster of Eida's Shield, whose impractical character design Shachiku finds distracting, and the various members of the Elite Four, each with tragic backstories rooted in the game's lore.

The story begins in the capital city of Falschlla. The initial arc establishes the premise as Shachiku speedruns the game and subsequently discovers he cannot leave. The second major arc involves hunting the Elite Four in a non-standard order. This includes the battle with Arachne in her castle, where Shachiku's coin-throwing strategy reduces a formidable foe to begging for her life, and the encounter with Raspi, where a lag-induced glitch sends him into the void. A notable subplot involves the lore of the world itself: the Goddess grew paranoid that the First Hero would betray her and banished him, causing him and his wife to transform into monsters out of grief and become the progenitors of the demons. This history creates a grim parallel as the people of the kingdom fear what the new hero might become. Shachiku remains unconcerned with this drama, focusing only on resetting the game to its proper ending. He acquires incomplete dummied-out items via glitches and continues to break the world's logic, forcing everyone around him to react realistically to a person who treats their lives as a sequence of frames to be optimized.