This is a Hong Kong Cat III movie. For those that don't know what that means. It means a lot of either violence or sex to push the envelope as far as Hong Kong law allowed at the time but sometimes with an excellent story. In this case it's for the sex but a very weak story.
Have to mention that the star of this movie is Rena Murakami from Japan. She was best known for starring in Sex and Zen, a classic Cat III movie. She also previously was in several (JAV) Japanese adult videos (Junko Kanô who is also in the cast was in several JAV movies in the 1980's) in the late 1980's. There is quite a bit of nudity and several sex scenes in this movie but not very explicit if that is what you are looking for. It goes as far as the law allowed at the time. They also are not very erotic.
The story is of Mona who married a very old, horny man with a bad heart condition for his money. But she also has some kind of debt which is never made completely clear, to a police detective. In the intro of the movie, Mona is pursued by a cop who is trying to apprehend Mona for the detective but Mona gets his gun and kills the cop. The old man's adopted (from a friend that died) son/nephew Wai is in love with Mona as well. Mona's cousin May comes to live with them and of course thinks she's in love with Wai. The rest of the story kind of meanders around so it can lead to the next sex scene. That is until the last 15 minutes. Then we get a sex scene that leads to a little action and the movie's finale. I don't want to give it away or there would be no need to watch this movie! The last 15 minutes were very good but the one hour and ten minutes to get there are not. It just seemed to drag on way too long.
The acting was alright. Nothing great but not awful. It just needed a better script or just more story. There are so many excellent Hong Kong Cat III movies but this is not one of them.