Mayumi Honjyo's nephew comes to stay at her home temporarily while job hunting. Reunited after five years, Mayumi is delighted—until one day, she catches him masturbating in his room. Flustered and trying to hide, the sight of his thick, throbbing cock stirs a mischievous desire within her. Right then and there, she gently kisses his lips, and their bodies soon follow. A new, forbidden relationship begins to unfold.