The dead woman was the mistress of a character easy to dislike, played by Alfred Cheung. He's your narrow businessman, interested in his wife's money and unfaithful. He feels suffocated in the marriage, but he brought it on himself. His wife is played by Irene Wan, and they have a baby boy. The husband of the dead woman is Simon Yam. Maybe he found out about his wife's infidelity and killed her, maybe not. He undertakes to get back at Cheung, but involves a thuggish pal who has a yacht. This leads to a kidnapping of Wan and son that's really not a planned-in-advance kidnapping.
The plot rapidly becomes more complex due to Cheung's behavior regarding ransom, which thoroughly alienates Wan. Amid the mystery and troubled relationships of everyone concerned, there is time for a lengthy (and unnecessary) making-love scene in which Wan goes nude. This seems fairly standard for quite a few 90s neo-noirs; and she is easy on the eyes and then some, without doffing any clothes. Meanwhile, it seems that Wan doesn't know whom to trust, and neither do we. This too is fairly standard for noirs that build variations on "Double Indemnity" and "The Postman". Like jazz, it's amazing how many ingenious variations there can be on the basic chords. The director keeps this movie moving and the result is entertaining with one proviso. The story has a shocking death in it that was not essential to the story, but certainly adds to its noir character.