This is really a sexually-themed Japanese movie. In the film, Hiroaki Mayama plays a company employee who's attracted to his senior coworker Kana, a nice and mysterious woman. One day, he suddenly gets an unexpected text message from her stating "Let's have sex tonight". He is very surprised but he decides to come. When he arrives, he is shocked by sexual life she's been leading in secret-one which he will soon become a part of himself.