Kiriko lives with her step-son Yoshio. Recently, Yoshio has started to grow up, and she is confused by the fact that she is now aware of him as a man. But Yoshio also secretly thinks of his step-mother, and fantasizes about being raped by his classmates, making him go mad with jealousy! The boy's Kokoro is stirred by the eroticism of his mother that permeates his daily life, and Kiriko's feelings that gently embrace him will lead to a conclusion. And then...