Italian director Silvio Amadio is most famous for two superior giallo thrillers he did in the early 70's, "Amuck" and "Smile Before Death". After that he directed a number of potboiler melodramas and at least one sex comedy with Italian lolita Gloria Guida (only one of which--"So Young, So Lovely, So Vicious"--is currently available in English). This movie was made before all of those, but it shares some elements with his later work. Like all of his later movie it is certainly a "sexy" film (at least by late 60's standards).
After a fight with her male lover, a beautiful girl (Catherine Diamante) goes to stay with a friend (the also-beautiful Ewa Green) on her private island where "no men are allowed". The friend is aggressively bisexual (as beautiful women usually are in these movies) and they soon develop a lesbian relationship. Their idyll is spoiled, however, when the male lover shows up. But the friend has a high-powered rifle that she won't use on pesky seagulls, but she might use on pesky men. . .
There is real lack of drama in this film, as the other reviewers said, until the very end at which point the drama becomes VERY drawn out. The two actresses are pretty, but they are simply not as compelling as the ones Amadio worked with later like Barbara Bouchet, Rosalba Neri, or Jenny Tamburi (or even Gloria Guida) and they often tend to kind of fade in the scenery. But what nice scenery it is! I can't fault the cinematography or the cinematic style at all. Unlike the other reviewer, I found Catherine Diamante more appealing than Ewa Green because, while the latter looks like an arch-European fashion model, Diamante has a more of a girl-next-door quality (and she does the same running-through-the-woods-while-throwing-off-all-her-clothes scene Gloria Guida would later make more famous in "Quella Eta Malizia").
I still can't figure out, however, the Italian title which translates to something like "Island of the Swedes". Ewa Green could be Swedish, judging from her first name, but she doesn't LOOK very Swedish. The Italians had all kinds of weird ideas about the Swedes though (see the Italian "mondo" movie "Sweden-Heaven or Hell?" sometime). Maybe they thought of all Swedes as a bunch of sexually voracious, gun-toting, bisexual lesbians? . .