The son is always fascinated by the sight of his mother, Miki, doing housework. However, the son doesn't stop there, and even has a forbidden fantasy of "Mom..." from the shadow of a pillar. One day, Miki receives a call from her husband saying "I can't come home today." Miki, who has been looking forward to their first sexual encounter in a long time, has no choice but to relieve her frustration by masturbating. The son, who has been peeping into the whole thing...