Lui, portrayed by Jacky Cheung](/actor/jacky-cheung), is a street racer entrenched in the world of triads, operating an auto shop while secretly smuggling cocaine for his boss, Brother Bing (Lung Fong). His criminal lifestyle significantly strains his relationship with his girlfriend, Katy (Ellen Chan), whom he often neglects and takes out his frustrations on. One day, Officer Bad Breath (Billy Ching), a friend of Lui's, informs him that a rival racer named Chang-pau is placing a hefty bet of HK$40,000 against him in an upcoming race against Joe (Max Mok), another racer who also runs an auto repair shop. To prepare for this challenge, Lui borrows HK$20,000 from Bad Breath.
On the night of the race, tension mounts as Lui and Joe engage in playful taunts before the competition. The race begins with Lui taking the lead, but near the finish line, Joe catches up. In a moment of desperation, Lui rams into Joe's car, leading to chaos as a fight breaks out between their respective crews when the police arrive and arrest Lui, Joe, and Lui's younger sister, Ann (Rachel Lee), who were unable to escape.
At the police station, Lui confronts his estranged father (Wu Ma), a seasoned officer who reprimands him for his life choices and involvement with crime, especially for involving his sister. Lui argues back, calling his father a hypocrite for his own corrupt history before the establishment of the ICAC, blaming him for contributing to Lui's criminal path.
After being released, Lui learns from his subordinate, Bull (Karel Wong), that Bad Breath attacked their shop as retribution for the debt. Lui retaliates by blowing up Bad Breath’s car, which instigates further violence until the police arrive again. The following day, Brother Bing demands that Lui settle things with Bad Breath and orders him to hand over Joe as punishment for saving Ann.
Reluctantly, Lui agrees, leading to Joe's capture and a brutal beating at the hands of Bad Breath’s gang. However, Joe is saved by Ann, who attends to his injuries after Katy’s departure. Ann and Joe’s relationship blossoms amidst the chaos, but Katy warns Ann about Lui’s possible reaction to their affair. When Lui discovers them together, he lashes out violently, and Ann grows frustrated with her brother’s actions, which leads to a confrontation with their father about his oppressive ways.
Simultaneously, Chang-pau and Lui meet to defuse their conflict, escalating into yet another race—this time for HK$500,000. Lui's father intervenes, urging him to abandon his reckless lifestyle for the sake of his loved ones. Shortly after, during a drug deal for Brother Bing, Lui's father witnesses an event that leads to a tragic car chase, resulting in his father's death in a crash. With his father's dying words haunting him, Lui faces the harsh reality of his choices at the funeral, while he wrestles with the desire to leave the triads behind.
As Lui grapples with his life choices, Joe proclaims his love for Ann, who fears for his safety due to her brother’s volatile nature. In a pivotal moment, Lui learns that Katy is leaving for Canada, prompting a desperate attempt to reconcile. A racing competition emerges once more as a way to settle scores and bring closure; however, the stakes are higher than ever. During the race, a malicious act by Bull results in Joe's car crashing into the sea, leaving everyone in turmoil.
With Joe's life hanging in the balance, Ann is faced with a heart-wrenching decision as tensions escalate between Lui and Bull, who seeks revenge for the unfolding tragic events. Ultimately, their chaotic lives culminate in violence as Bull's greed leads to a catastrophic misunderstanding. As the police close in, Lui, in a desperate bid to save Bull, finds himself in the heat of a shootout, leading to a dramatic climax that questions loyalty, choices, and the ramifications of a life lived on the edge.
