As the movie begins, a bankrupt Italian count has just committed suicide. One of his creditors has taken over the family villa, but he allows the widow, the mother, and the three adult sisters to stay on. The creditor is a wealthy businessman, but also basically an uncouth peasant (who fancies himself an opera singer). Still, the dimwitted, sex-crazed sisters try to seduce both him and his shy, virginal son who accompanies him. But both men end up falling in love with the voluptuous widow (Senta Berger) creating a kind of incestuous love triangle.
If you've seen a lot of Italian sex comedies, you know they tend to vary greatly from relatively sophisticated and arty to really, really stupid. This one is more on the arty side. The plot kind of resembles the Anton Chekov play "The Cherry Orchard", but played more for laughs than tragedy. The movie also references the most famous arty sex comedy of this era, the Laura Antonelli film "Malizia", with its plot line of an "incestuous" relationship between a son and a stepmother (although the son here is a young adult rather than an adolescent).
This is a very good role for Senta Berger and the two male leads are also quite good. They kind of underused the domineering, seanced-obsessed mother though, and they definitely underused the sexy Erika Blanc (one of my favorite Italian exploitation actresses and main reason for seeing this), who plays the oldest daughter. The unknown actress who plays the youngest daughter has some memorably sexy scenes, but they seem completely grafted onto the rest of the movie. (Her gratuitous nude scenes are enjoyable, but really her whole role is completely gratuitous). She also looks to be little more than half the age of Berger and Blanc (but obviously they wanted a panty-flashing "lolita" to complement the two voluptuous older "madonnas").
I wouldn't recommend this to most people, but if you like Italian sex comedies (which, I have to admit, I kind of do for some reason), you could far, far worse than this one.
