The story of two friends and their different attitudes to women. Keith works in advertising and wants to marry his longtime girlfriend Wai but she is more intent on furthering her career as a photographer. His best friend David, a hairdresser, fools around and wants him to do the same and not be faithful to his girlfriend. When Keith is rebuffed by Wai, he is readily seduced by the new girl in the office Nancy. Meanwhile David falls for An An Yu but due to a misunderstanding with her brother he is warned to stay away. Things complicate and Keith becomes jealous of David whom he suspects of playing around with both Wai and Nancy. Inevitably their relationships with women suffer and they get their just dessert.
So Keith begins suspecting that his best friend David is fucking both his girlfriend Wai (sometimes referred to as his wife in the subtitles, but girlfriend is the more correct one) and his mistress Nancy. David confesses to him that he didn't fuck his girlfriend Wai but he did fuck his mistress Nancy. Although, David and Wai nearly kiss when they go out one night and are just interrupted by a phone call (1:15:20). No sex scene between David and Nancy. All the sex scenes in the movie are between Keith and his girlfriend, and Keith and his mistress.