Koi is the wife of Nobuo, a kendo practitioner. She is having an affair with Kozuka, one of her husband's students, and enjoys secret rendezvous with him when her husband is not looking. It's not that she doesn't love her husband, she just wants him to love her more, to look at her... those are Koi's true feelings. Koi seduces the young and strong Kozuka, and relieves her loneliness and desire, but gradually she finds herself unable to be satisfied by ordinary things. Then she begins to ask Kozuka to do it close enough that she can feel her husband's heartbeat...