Gu Changqing, an international mercenary, vanishes from the battlefield and falls into the “Infinite Corridor,” which devours a billion lives. Here, every instance is an execution ground: medieval castles, cyberpunk wastelands, Lovecraftian abysses... Those who fail become another erased number on a statistics screen. Accustomed to working alone, he rescues Lin Yan, a pale and frail young man, from a swarm of mechanical beasts. Lin Yan is no match for anyone in a fight, but his exceptional intelligence repeatedly breaks them out of seemingly inescapable traps.
The two men form a deadly team: Gu Changqing carves a path with his blade, while Lin Yan steers them with his wits. When Lin Yan dies in the final instance to protect Gu Changqing, the cold System reveals the truth: in this game, only the victor can wield the key to creation. At the cost of his own existence, Lin Yan gives Gu Changqing “absolute rationality.” “Take my mind with you, and see every possibility.”
Gu Changqing inherits two SSS+ traits and grows smarter through battle as he sweeps through the remaining instances. On the day he reaches the summit, the System grants him the [Key to the Real Universe] and declares, “Your universe is waiting for you.” But the price is that Lin Yan has vanished into nothingness... until Gu Changqing stares at the key in his palm and notices the dimensional coordinates Lin Yan left behind. This time, the hand that wields the blade will fight to create. At the end of the Final Observer’s path, he will trade eternal solitude for a reunion.
