Sumika and her daughter Yuka share a close bond. When Yuka reaches dating age and starts a relationship with her boyfriend Ryo, the families grow close, becoming almost like one. Taking the opportunity while her husband is away on a business trip overseas, Yuka plans to have Ryo spend the night, with Sumika's approval. But on the day itself, noticing something suspicious in Yuka's behavior in her room, Sumika gives in to her own desires and masturbates to calm her emotions. Meanwhile, Ryo, overwhelmed by nervousness, retreats to the kitchen to spend time alone. Drawn to him, Sumika approaches, exuding pheromones and stirring his heart. As family bonds and shifting romantic feelings collide, a complex and thrilling story unfolds.