A family consisting of a patriarch, his much younger wife, his troubled sister, his sons, and their wives go on a vacation to a remote Mediterranean island where years earlier the father and sons had murdered the lower-class lover of their sister/aunt. At first there are a lot of sexual shenanigans--one of the brothers succumbs to the temptation of his impotent brother's hot-to-trot wife, the father's young wife is carrying on with his other son right in the room where the man's own wife slumbers. Eventually though the guests begin to be picked off one-by-one in rather grisly fashion, and the movie gets a lot more interesting. As others have said, this movie greatly resembles the Agatha Christie murder-mystery "Ten Little Indians", even more so than some of the other Italian gialli that also mined that famous book for inspiration like "Five Dolls for an August Moon" and "The Weekend Murders". (In fact, if you're very familiar with the book, you might be able to guess the identity of the murderer in this one).
The male cast here is indeed quite impressive including Arthur Kennedy (as the father) and John Richardson, Massimo Foschi, and Venatino Venetini as the sons. As for the female cast, well, they do take off their clothes a lot. Actually, the most recognizable might be Sofia Dionisio (aka Fabiani Flavi), the sister of Silvia Dionisio and one-time sister-in-law of director Ruggiero "Cannibal Holocaust" Deodato.
The director of THIS movie, Fernando Baldi, was talented if rather erratic. He's most well-known for spaghetti Westerns like "Texas Addio" and "Blindman", but he also did some risible crap like "Terror Express". This movie is definitely better than the latter, but perhaps not quite as good as the former. It's not a classic giallo,but it is a respectable effort.
