City Under Siege

Many years ago in Malaysia, Japanese scientists experimented with mutagenic gases. A lab explosion wipes out everyone inside and releases the agents into the surrounding area. The incident seeds the mutations that will ripple through the story's future.

Sunny is the orphaned son of a former knife-throwing master and is taken in by his uncle to perform as a clown. He longs to master his father's knife-throwing skill, despite the taunts from Zhang and his cousins in the troupe. His childhood is marked by rivalry and unfulfilled dreams.

Sunny is used as the point man for a cave expedition rumored to contain treasure. They uncover crates, open capsules, and release mutagen gas as they retrieve gold plates. The mutagen mutates the group, and Sunny accidentally kills Zhang's younger brother before escaping.

Exposed to the mutagen, Sunny collapses aboard a smuggler's ship heading toward Hong Kong. The crew discovers his altered state and throws him overboard in panic. He survives at sea and begins a new, changed life.

A few days later, Angel Chan, a reporter, discovers Sunny in an obese state after he wakes from a coma. He is taken to a safe house where he drains excess fat and water while sleeping. When he wakes, he has regained his form and discovers superhuman strength and heightened abilities.

Sunny tries to contact his uncle but learns he has been arrested by the Malaysian police for the incident. He is also plagued by incessant mosquitoes, adding to his sense of dislocation. The past seems to close off as the present demands answers.

Armored cars, banks, and jewelry shops are blown up while several medical experts are abducted. A mutant-couple disguised as detectives begins investigating the surge, linking the mutating people to a growing conspiracy. Public fear grows as more mutations surface.

Angel is fired from her program to make way for a new face, and Sunny orchestrates a dramatic hostage-disarm scene to save the day. His televised heroism leads to an interview in which Angel becomes his agent and manager. The pairing instantly rockets Sunny into the spotlight.

The mutated members of the troupe see Sunny as the source of an antidote and attempt to kill him. Sun Hao and Xiuhua intervene to defend him, and a mutated troupe member is killed in the confrontation. The fight reveals Sunny's new weakness to cold.

Doctors conclude Sunny's blood contains antibodies that can neutralize the poison without removing his mutant powers. Sun Hao and Xiuhua decide to become Sunny's bodyguards to shield him from further attacks. The medical insight shifts the balance of the conflict toward Sunny's side.

During a commercial shoot, Zhang's troupe subdues Sunny and drinks his blood. Rather than curing him, the drinking accelerates his mutation. Xiuhua dies from injuries sustained in the escape, and Sun Hao vows to train Sunny to face Zhang and the remaining mutants.

In the climactic showdown, Zhang injures Angel while trying to seize control. Sunny uses his sharpened knife-throwing skill to kill Zhang, ending his threat. In the ensuing chaos, Zhang's mutant cousin dies in a suicide explosion orchestrated by the mutants.

With the danger past, Angel and Sunny settle into a peaceful life together. They start a family and have a son, sealing their extraordinary story with ordinary happiness. The epilogue shows a hopeful future built from a turbulent past.