Yuri, a high school student plagued by catastrophic bad luck, seeks escape in the highly anticipated VRMMO Blade Skill Online, a game where luck is a controllable stat. Following what he believes to be an official strategy guide, he carefully designs his avatar for a carefree in-game life, choosing the Summoner class, a bow as his weapon, and investing every stat point into luck. His plan collapses upon logging in. The guide was a hoax, planted by trolls on an unsecured developer website; the Summoner class is widely considered useless, the bow is the weakest weapon, and a pure luck build is ridiculed as entirely ineffective in combat. To compound his misery, the random avatar generator gives him the appearance of a beautiful silver-haired, red-eyed girl.

The story follows Yuri in his female avatar as he refuses to accept defeat. Determined to turn his disastrous build into an advantage, he dedicates himself to mastering its hidden potential through unconventional tactics and flaw exploitation. His persistence pays off in spectacular fashion. By leveraging his high luck stat to tame rare and powerful monsters, he rapidly gains strength and notoriety, transforming from a laughingstock into an overwhelming player known by terrifying nicknames such as Raid Boss, Wild Last Boss, and the Demon Lord. This meteoric rise, however, puts a target on his back. The game developers, embarrassed that their incompetence has been exposed by a player using a troll build, become antagonistic. Instead of celebrating his success, they repeatedly nerf his abilities and adjust the game in an attempt to drive him out.

The narrative is driven by Yuris confrontations with both the developer-hostile events and the wider player base. A major early arc revolves around a large-scale PvP event where Yuri aims to prove the viability of his build by crushing the competition that ridicules him. Later, during a guild war, a rival player known as Baldy unites nearly every other guild in the game to finally defeat the undefeated Demon Lord, forcing Yuri to lead his own guild in a desperate battle against the entire server. The story is action-oriented and comedic, with Yuri portrayed as a hot-blooded and spirited competitor who lives for the thrill of the challenge, while the developers increasingly resort to desperate measures, including importing top players from other VRMMOs, to stop him. The fact that his in-game avatar is a girl is used sparingly as a source of comedy, such as attracting unwanted attention, rather than being a central focus of the plot.