One Martial Art Manual Conquers All

Nie Feng, a former military king from a mysterious army, now a small security guard with extraordinary skills.  Once a prominent member of a shadowy organization, Nie Feng's life is derailed by a catastrophic mistake, forcing him into premature retirement.  He struggles to find meaning in a life that once brimmed with purpose, now reduced to mere survival in a world that has seemingly abandoned him.
As Nie Feng grapples with his new reality, an unexpected proposition emerges, offering a way out of his financial woes: a job as an assassin.  The task is daunting, requiring him to take a life for a substantial reward.  This moral dilemma torments him – can one put a price on a life?  Is survival justification enough for ending another's existence?