Sōichirō Anzai, a fine arts professor at a certain university (played by Akira Emoto), is getting older and feels his physical strength waning. He laments the stunning beauty of his wife, Yuko (played by Naomi Kawashima), yet is dissatisfied with their dull and monotonous sex life and his own impotence. The couple accidentally encounters a young and suave photographer, Ken'ichi Kimura (played by Kōki Ōsawa), and a brief conversation between Yuko and Kimura brings a pang of jealousy to Anzai, creating an illusion of renewed youth. From this point on, Anzai embarks on a dangerous experiment; he deliberately invites Kimura to their home and attempts to experience intense jealousy through the ambiguity between his wife and Kimura. Meanwhile, he writes his true feelings in a private diary and deliberately allows Yuko to see it. An underlying desire for Kimura triggers an unprecedented pleasure for Yuko as she experiences something new with her husband. The couple ventures further and further into their pursuit of ultimate pleasure... This film is adapted from the eponymous work of Japanese erotic writer Jun'ichirō Tanizaki.