The film opens with MPS officer Cheng Carol Cheng and her nephew Hsiao-Sheng Alfred Cheung Kin-Ting, riding a coach to Hong Kong. They are painted as deeply loyal communists, roaring through the journey with My Motherland on their lips, smoking, spitting, and hurling sharp verbal barbs. Simultaneously, Superintendent Cheng Lam Chung briefs Chief Inspector Wu Tony Leung Ka Fai about a high-stakes case: Wong Ti, known as Niu Michael Chow Man-Kin, has confessed to smuggling drugs from the Golden Triangle into Hong Kong. He claims a deal with the Royal Hong Kong Police could spare him the PRC’s capital punishment if he helps prosecute his boss, drug lord Su Kuo-Jung Sunny Fang Kang. This odd alliance is what brings Wong to Hong Kong, and Wu is tasked with receiving him and guiding Cheng through the case.
Wu’s preliminary handling of the case is chaotic from the start. They meet at a cross-border coach station, and it shocks Wu to discover that Wong is abused by Cheng and packed inside a small bag for delivery. An emergency with an oxygen mask pulls Wong back from the brink, and the police detain him in a makeshift command post set up in a local apartment. Back at headquarters, Cheng remains skeptical about technology’s promise to improve efficiency; after a brutal malfunction of a lie detector, she proclaims that machines are unreliable and that human skill and intuition must come first. Wu expects to house Cheng in a hotel, but a travelers’ peak season forces them into a Kowloon Tong hostel, where they stumble onto simple TV programmes and a vibrating bed, momentarily softening the hardened posture of both.
Wong then makes a desperate break for freedom. He distracts and knocks guards aside and escapes, prompting Cheng to reject the so-called efficiency of the force and refuse to help retrieve him. The plot thickens when Zhao Ziyang, the General Secretary of the CCP, phones Cheng and threatens exile to the desolate Daxinganling if she cannot capture Wong—an ultimatum that tests her loyalty and fuels a rift with CIP Wu.
Determined, Cheng pivots toward a more aggressive pursuit, pressing for a Hong Kong police operation under her command. Yet her plan to arrest Su Kuo-Jung would trample on human rights and violate Hong Kong law, deepening the rift with Wu. Frustrated by the city’s hesitation, Cheng confronts Su alone in his office; Su refuses to talk about Wong and dispatches his henchmen to assassinate her.
Cheng and Hsiao-Sheng escape harm but must be moved for protection. Superintendent Mok [Lam Chung] suggests letting them stay at Wu’s house, hinting that the arrangement could bolster Wu’s career prospects even after the 1997 sovereignty transition. The presence of Cheng injects tension into a family-like alliance, and the result is a micro civil war between the two factions—propaganda battles erupt as patriotic songs are sung through the walls between them. The conflict reaches a fever pitch over breakfast, with the two men donning military uniforms and debating left-leaning versus right-leaning appendages, until Wu, an ambidextrous officer, mediates a tenuous temporary truce.
Niu’s movements become even murkier when he reestablishes contact with his brother to flee Hong Kong. He turns to Su for help, but Su’s men ambush him in a street shootout. Niu survives, but his brother is wounded; a witness hands over a letter from the brother hinting at a village called Sau Mau Ping, triggering a police search of the locals. Cheng builds rapport with Sichuan-born villagers, eventually learning that Niu frequents a karaoke bar where he also meets his lover Hsuen-Pi [Sheila Chan Suk-Lan]. The squad shadows Hsuen-Pi, peeling back another layer of this tangled web.
Back home, Cheng finds Hsiao-Sheng dressed in a National Revolutionary Army uniform, surrounded by veteran comrades and Colonel Wu. She takes this encounter as counter-revolutionary behavior and challenges the veterans to a drinking contest; she wins with a clear head. Wu later shows her the city at night from above, and as they return by elevator, a blackout reveals the city’s “dark side.” When the lights return, the moment leaves them holding hands—and Cheng experiences her first taste of love.
With renewed resolve, Cheng and Hsiao-Sheng hatch a plan to pose as Niu’s lawful wife to extract his contact from Hsuen-Pi. Yet Niu remains elusive, hiding at Hsuen-Pi’s home and slipping away again after a scuffle with Cheng. The hunt intensifies as Wu receives intelligence that Niu plans to rob a jewellery shop; detectives position themselves around the store, but the cover is blown when Chan drops his revolver while trying to rescue a girl in the street. A tense street chase culminates in a narrow corridor where Cheng proves her marksmanship, but Niu disappears once more.
Mok imposes a hard three-day deadline for Wu and Cheng to capture Niu. If they fail, Wu will be sent to Tai A Chau Detention Centre and Cheng will be sent back to China. New intelligence surfaces: Su has begun meeting drug dealers in nightclubs, and the police require a female undercover to listen in. Cheng volunteers and goes undercover; as Su brings her to his place, he meets Niu, who demands three million dollars in exchange for fleeing and reveals that cannabis stored at San Yik Godown is worth twenty million dollars. After a long bargaining session, Su kills Niu, and Cheng escapes to the wrong San Yik Godown. There, she tortures the godown keepers to extract information but is captured herself. She is imprisoned and prepared for deportation.
Wu’s team pieces together the godown's true location and finds a cannabis stockpile at the correct Sun Yik Godown. The squad breaches the facility, but Hsiao-Sheng is seized by the godown workers, and Su and his henchmen tie up the team and pour petroleum to burn them. Just as the blaze starts, the lights go out again and Nationalist veterans surge in to rescue the squad. Wu fights back, and order is restored. Superintendent Mok arrives with a daydream of promotion, and Cheng and Colonel Wu finally forge a working alliance, a pragmatic collaboration between the Communists and the Nationalists.
At the border, Cheng hands Wu a sincere letter of apology for her temper and a note of gratitude for their collaboration during the mission. She confesses that it was the first time she held a man’s hand, and that memory feels precious. With 1997 on the horizon, she looks forward to continued cooperation and a future built on mutual respect and pragmatic alliance rather than ideological purity.
Cheng Shih-Nan Carol Cheng and Hsiao-Sheng Alfred Cheung Kin-Ting stand as a testament to a complicated, fragile partnership that can bridge deep political divides when pressed by circumstance, and the film closes on the promise that, in a changing city, human connection and strategic cooperation may matter more than rigid affiliation.
