Yuna & Masashi couple and Ai & Teruhiro couple, who attend the same university and belong to the same club, often go on couple dates and are all close friends. With their respective anniversaries approaching, the four of them came on this trip. Even knowing it was wrong, Yuna and Teruhiro ended up having a two-day one-night trip of secret sex behind their respective boyfriends and girlfriends. 'I love my boyfriend, but the sexual compatibility with my best friend's boyfriend was the best...'
