A sexually-themed Japanese movie based on a novel by Shu Satami. The film is about a publishing company employee - Hiroaki Mayama who is attracted to his senior coworker Kana,  a woman who seems to have a nice, clean image while also giving off a certain air of mystery. After several failed attempts to hit on her, he suddenly gets an unexpected text message from her bluntly stating Let us have sex tonight. When he arrives, he finds a suspicious DVD and witnesses the shocking sexual life she has been leading in secret-one which he will soon become a part of himself.