A young man named Son finds himself attracted to his new stepmother, Mao Hamasaki, despite their age difference. Feeling that he can't control his desires any longer, Son decides to leave home. However, before doing so, they all go on a family trip to a hot spring resort. While Father passes out drunk, leaving them alone together, Son gives in to his urges and initiates a passionate encounter with his beautiful stepmother. Despite feeling guilty about their incestuous relationship, Mother cannot resist her son's advances and indulges in one night of forbidden pleasure. As they lose themselves in their lustful desires, both mother and son forget about societal norms and dive headfirst into this taboo affair. Note: The contents may vary depending on the distribution method.