A savage work that explores human sexuality and its articulations with political stances and religion: Two couples of university students swap their partners, one, Yukiko and Shinichi experienced and one, Hirochi and Yasuko unmarried and first time in an isolated motel. Later, at the seaside one of them is attacked by two maniacs, who leave the husband unconscious and rape the woman. After the event that was supposed to be traumatic, the attacked couple find themselves interested in the two aggressors and the gratuitousness of their act, and goes to look for them in the surroundings of the motel. They discover that they are part of a sect that has sexual freedom and self-support as slogans. At first reluctant, but soon giving way, the couple end up joining the secret sect and isolate themselves from the world, but things get complicated when the other couple decides to look for them.
Swapping scene at the beginning of the movie. The female from the inexperienced couple, although she seems to really enjoy the sex, lets her partner and the other guy know that she doesn't really like the idea of them swapping.