Vampyros Lesbos

Soo-hyeok and Yeon-ji are faithful couples. Although Soo-hyeok is faithful during the day, he wants to be rough at night, however, Yeon-ji is still faithful at night. Su-hyuk uses his junior In-seop to turn Yeon-ji into a hot woman. In-seop manipulates Yu-ri to defile Yeon-ji, but falls in love with Yeon-ji and covets her. Soo-hyeok is angry that Yeon-ji and In-seop slept. Soo-hyeok covets Yu-ri for revenge, but gets caught by his wife Yeon-ji, who declares her union with Yu-ri.
Soo-hyeok must reveal that Yu-ri is actually bisexual, not gay, to protect Yeon-ji. Soo-hyeok shows Yeon-ji a scene where In-seop and Yu-ri have sex. However, Yu-ri and In-seop’s sex is not good enough. In-seop forcibly scurries Yu-ri at Soo-hyeok’s order, and eventually runs to Yeon-ji when he finds out that Yeon-ji is disappointed in her. The two find a new gender identity.