Widow Sex War (1988)

After her husband dies, Aiko becomes the caretaker of an old apartment she inherited from him. By chance, her high school classmates Kaoru and Miyuki live in the apartment. Both are widows and each has a boyfriend. Then Toru and Ikuko, a couple, move into the apartment. Ikuko is a detective, and Toru is in charge of housework and sex. Since Toru's arrival, the three widows have had many worries. To make matters worse, a surprising truth is hidden about the man who is pursuing Aiko and Kaoru and Miyuki's boyfriend...