On a tense night in Hong Kong, the Hero Gang unleashes Pioneer I, an armed robot, to crash a bank heist as the city’s police scramble to gain the upper hand. Maria Sally Yeh is a fiercely loyal member of the gang and to its enigmatic leader Ben Lam Kwok-Bun, carrying out brutal acts without hesitation, even wiping out the mechanical maintenance staff who try to make a run for it. Master Lam Ching-Ying, a veteran elder of the gang, grows increasingly dissatisfied with Maria’s cold-blooded approach. The tension deepens when Maria discovers that the leader is obsessed with robotics and has built a female armed robot named Pioneer II, modeled after Maria’s own face, a revelation that fuels her growing hatred toward the doppelganger.
Reporter Chong Chi Keung Tony Leung is fired for failing to photograph Pioneer I during the bank raid. Curly John Shum Kin-Fun, who works in the police Research Department, invents a cannon that could counter robots, drawing the ire of his superiors. Whiskey Tsui Hark, a younger member of the Hero Gang, resigns in frustration at the gang’s stagnation. Whiskey later befriends Curly at a bar, and soon the two are swept into danger when Pioneer II is sent to kill Whiskey. During the chase, Pioneer II malfunctions and Whiskey, along with Curly, manage to escape, with Whiskey secretly harboring a crush on Maria. The pursuit also draws Curly into the crosshairs of the police as a person of interest.
Curly and Whiskey flee to a shack where Curly works on Pioneer II, reprogramming it to obey his commands. The process also stirs something human in the robot, softening its responses and blurring the line between machine and person. Maria responds with force, bringing Pioneer I to the shack to kill Whiskey. Curly orders Pioneer II to attack Pioneer I, but Pioneer I is protected by a “Counteract Bullets Device,” rendering Pioneer II’s assault ineffective. Master arrives in disguise and helps Whiskey and Curly escape, fleeing to a shipyard. Chong chases the trio and performs a lighthearted, farcical skit with Pioneer II, who begins to display more human-like behavior. Chong then reports to the police, leading to Curly and Whiskey’s arrest, while Pioneer II falls back into the Hero Gang’s clutches to be reprogrammed.
As the story unfolds, Chong grows sympathetic toward Curly and Whiskey and, with Master’s help, sneaks into the Hero Gang base to free Pioneer II. Master confronts the gang’s leader in a brutal duel and discovers that the leader has turned Master himself into a robot. The fight ends with Master overpowered and captured, while Chong, Curly, Whiskey, and Pioneer II manage to slip away.
Chong, now allied with Master, helps Curly and Whiskey escape from prison and the quartet moves to confront the Hero Gang at its stronghold armed with Curly’s cannons. Pioneer II takes on Pioneer I in battle, and Curly and Whiskey install cannon emplacements around the base. Chong races to rescue Master, who becomes a key player in the final showdown. After a grueling conflict, Pioneer II is momentarily cornered by Pioneer I; Maria delivers a sharp blow that buys Pioneer II a window of opportunity, and the automaton fires a decisive shot that takes out Pioneer I and disrupts the gang’s plan.
The gang’s leader races to activate the colossal final weapon, Pioneer III: The Ultimate Pioneer, only to have Chong and Master slip inside to intervene. In the rooftop clash that follows, Master uses the giant joint of the robot to topple the leader. A miscalculation by Chong sends the colossal machine into an uncontrolled arc, but he and Master jump to safety as the leader plummets to his death and Maria follows him, choosing a fatal end.
In the closing moments, Curly, Whiskey, and the now anthropomorphic Pioneer II begin a quieter, hopeful life together, while Chong walks away with the memories of his pursuit of headlines, having abandoned the photos he once chased. The story ends on a note of reconciliation between human and machine, and a hint of a future where coexistence might outlast violence.
