In Cambodia 1975, the eight-year-old Wai Lok-yan witnessed the tragedy of his parents being killed by Ray Lui (Paul Chun) while hiding in the closet with his younger sister. Back then, Yan's father Wah (Philip Ko), Ray and Seung (David Chiang) were war comrades working for the CIA in Cambodia. Later Ray gone rogue and works for the Khmer Rouge and in order to take the information gathered by Wah, he killed Yan's parents, while Yan's younger sister also dies in a fire. After this incident, Seung takes the orphaned Yan to Thailand, where he became a Thai Air Force Pilot.
In 1995, Yan (Andy Lau) learned from the newspaper that Ray, who has become a billionaire from dealing arms for many years, is attending an event in a hotel in Thailand. Yan was determined to take this opportunity to avenge his parents, but Ray was wearing a bulletproof vest and the assassination hit failed. However, Yan's friend Mark, who is also Seung's son, was caught and killed. Yan managed to leave the scene with the help of Ray's mistress Mona (Rosamund Kwan), whom Ray only treats her as a doll.
In order to escape the mine on assassin searches form Ray since Ray has close ties with Thai Military officials, Seung arranges Yan to go to the United States. With help from the CIA, they decide to have Yan get close to Ray's daughter Crystal (Jacklyn Wu), who resides in San Francisco, and slowly get close to Ray and ultimately killing him.
At that time, Crystal was kidnapped by the Black Tiger Gang and the gang demanded Ray to return money that he owed. The CIA had close ties with another gang, Wah Fuk, and arranges Yan to be the temporary leader of the gang under the name Mandy Chan. Yan leads the Wah Fuk Gang to terrorize the Black Tiger Gang and rescues Crystal. Later, Yan successfully develops a marital relationship with Crystal and Yan becomes his enemy Ray's son in-law.
In Yan and Crystal's wedding, a shootout occurs and General Buboei's (William Ho) son Major Bodar (John Ching) was shot and killed by the Hong Kong police. Ray decides to take Yan to Cambodia to see Buboei and use Yan as the scapegoat of Budar's death. During a pregnancy test at the hospital with Crystal, Yan gets a call from Mona telling him to meet in a hotel room. There, Mona informs Yan of Ray using him as a scapegoat. As Yan and Mona still love each other, they briefly make out in the room before being interrupted by Crystal's entrance. Mona pushes Crystal on a glass table and attempts to kill her until Yan stops her form doing so.
When Crystal is sent to the hospital, Yan explains to Ray of the incident by saying that Crystal caught him with a prostitute. Yan also sees Seung in the hospital who gives him a tracking device for him to take to Cambodia. Later, Yan reveals to the unconscious Crystal about his true identity and his intention to kill her father and stating either himself or his father will only return from Cambodia. Crystal awakes and asks him to promise her not to kill her father.
In Cambodia, Ray meets up with Bubeoi who show him pictures of Yan as a pilot and a photo of Ray with the CIA and he suspects Ray to be a traitor. Yan trigger the tracking device and the Thai Military arrive. Ray, who knew along that Mona injured her daughter, shoots and kills Mona while also attempts to kill Yan to prove he is not a traitor. A big action scene occurs where later Ray and his henchman Dog (Ben Ng) takes Bubeoi hostage and Yan chases them on a helicopter. Dog kills Bubeoi in the process, before he was killed by Yan with a firebomb. In the end, Yan finally confronts Ray at gunpoint, but he finally decides to not kill him and let him be taken by the military force instead.
In the end, Yan receives pictures of Crystal and their son from Seung. Seung also brings his son from Hong Kong and a letter written by Crystal to Yan. She states that Mandy is the past and she is not so familiar with the name Wai Lok-yan and wants to have some time to familiarize it, hinting that she might get together with Yan again in the future.Andy Lau as Wai Lok-yan / Mandy Chan
Rosamund Kwan as Mona
Jacklyn Wu as Crystal Lui
Paul Chun as Ray Lui
Ben Ng as Dog
David Chiang as Uncle Seung
Philip Ko as Wah
Nam Yin as Ray's henchman
William Ho as General Buboei
John Ching as Major Bodar
Parkman Wong as Officer Cheng
Four Tse as Ray's bodyguard
Wong Kam-kong as Military officer
Victor Wong as Uncle Nine
George Cheung as Uncle Tung
Paula Eliso as Beaten Girl
Edward Corbett as CIA
Maggie Wong as Yan's sister
So Wai-nam as Ray's bodyguard
Lee Siu-kei as gambler
The Romantic Flame Never Burns Out (愛火燒不盡)
Composer: Tsui Ka-leung
Lyricist/Singer: Andy Lau
The film grossed HK$14,839,584 at the Hong Kong box office during its theatrical run from 2 to 30 August 1995 in Hong Kong.