After a heated argument with her husband leaves her emotionally shaken, Sawako tries to calm herself by masturbating, but her son Yukio suddenly walks in and catches her in the act. Embarrassed and flustered, she feels her chest tighten with anxiety. Yet, as Yukio stands frozen, staring at his mother's aroused state, Sawako gathers her courage, pulls down his pants, and takes the initiative. Overcome by her bold move, Yukio loses control, captivated by his mother's intense touch, and succumbs completely to his own desires. The bond of mother and son now transforms into a forbidden, passionate relationship.