Fang Raon, newly seeing and moving in Black Online, joins a newbie party led by the kind Tessa, her mage sister Rosabella, and the arrogant, veteran-smurf Assassin Dewrey. Their first venture into the sewers, a standard "kill rats and dogs" quest, quickly escalates from a mundane grind to a grim reality check. Tessa's accidental scream attracts angry rats, forcing Fang Raon to use his shield with surprising force, hinting at a natural combat instinct. The party's journey culminates in a tense raid on the 1st Floor Boss, the Red Orc. Fang Raon's quick strategic advice to Rosabella about mana conservation proves prescient when the boss enters its fiery third phase. Despite their combined efforts, Tessa dies, scorched into ashes by the boss's flamethrower attack, a brutal reminder of the game's "one life" stakes and the fragility of their virtual existence. Immediately after, Junior's larger, better-equipped party, who had joined them for the raid, reveals their true colors, attempting to strong-arm Fang Raon and his remaining companions out of their share of the loot. Fang Raon, seeing through their "trick," refuses to disarm, leading to a desperate battle. Dewrey and Rosabella fall, but Fang Raon, harnessing a cold, sadistic focus, systematically dismantles Junior's party, culminating in a brutal one-sided slaughter. He emerges victorious, claiming the treasure chest and the spoils of his vengeance, but the cost is clear: the virtual world offers freedom, but also a raw, unforgiving brutality. This visceral experience galvanizes his resolve to not just survive, but to master this world.

Fresh from his bloody victory on the 1st floor, Fang Raon embarks on a solo clear streak, conquering the 2nd, 3rd, 4th, and 5th floors of the Tower of Black in rapid succession. This rapid ascent garners him "Floor Announcements" and growing notoriety on Black Online's forums, but the true stakes lie outside the game. After his first day of combat, he logs off to find his real body completely paralyzed, a sudden and terrifying acceleration of his Optineurodegenerative Syndrome. The doctors grimly inform him he's a "ticking time bomb," with only a couple of years before becoming brain dead, and he's moved to a caretaker facility. This real-world deterioration, however, directly contrasts with his in-game experiences. When he returns to Black Online, he feels stronger, his vision clear, his movements fluid. He receives unique rewards from his solo clears: enhanced gear (Refined Sword, Steel Shield, winter clothes), powerful skill scrolls (Sword Stab, Hard Slash, Dodge Roll), and valuable stat-enhancing tattoos and piercings. Most critically, he finds an Enchanted Compass and Escape Marbles, crucial tools for his continued solo adventures. The stark contrast between his virtual strength and real-world fragility, coupled with the mysterious letter's promise of a "cure," creates a compelling central mystery: is Black Online causing his rapid decline, or is it, somehow, the only thing keeping him alive, offering a path to recovery even as his body fails?

Fang Raon’s solo streak leads him to the 6th floor, a tropical "paradise" and "recruitment floor." Here, a seemingly random encounter with an eccentric old man named Rock, who reprimands his "sloppy" combat, leads to an unexpected mentorship. Rock, a "Demon Instructor" and guild master's grandfather, forces Fang Raon into grueling physical training on the beach, pushing his in-game stamina and speed to their limits. This training reveals a crucial aspect of Black Online's realism: physical exertion in-game translates to real-world fatigue, a shocking revelation that deepens the mystery of his condition. Beyond physical prowess, Rock introduces Fang Raon to "General's Game," a complex strategy game within Black Online. Fang Raon, despite being a novice, displays an astonishing ability to control all ten soldiers simultaneously, a feat that stuns even the seasoned Rock. This demonstrates Fang Raon's exceptional mental acuity and strategic brilliance, suggesting his true "cheat" might be his mind's unparalleled processing power, which directly contradicts his physical decline. This mentorship and the mini-game reveal a new dimension to Fang Raon's talent, preparing him for the complex social and strategic challenges of guild life and higher floors.

Rock, impressed by Fang Raon's talent, assigns him to Rose Records' "Fourth-Liners" recruitment exercise, pushing him into a leadership role despite the skepticism of Della Rose, the guild master and Rock's granddaughter. Fang Raon immediately clashes with Miranda, a stern guild executive, and faces a team that initially doubts his capabilities, preferring the more conventionally "soldier-like" Machary. In the King of the Hill-style evaluation raid, Fang Raon’s team is initially wiped out by Machary's superior strength and tactics. However, Fang Raon, now at Level 2, uses his newly gained 100 stat points to specialize in Stamina, Attack, and Vitality, which dramatically alters his combat ability. His strategic genius shines as he orchestrates a complex trap, using environmental manipulation (Slippery Floor spell) to turn the tide. He confronts Machary directly, showcasing his enhanced physical prowess and tactical intelligence, ultimately securing victory for the Red Team. His leadership, initially doubted, earns grudging respect. Back in the real world, his doctors are baffled: Fang Raon's vision has returned, and his motor functions are slowly recovering. The physical changes from his in-game training are now undeniably manifesting in his real body, confirming Black Online as his cure, not just an escape.