Taku, a second-year university student living at home, leads a carefree life, untouched by the struggles of the real world. His days are filled with casual interactions with his parents, 父ちゃん and 母ちゃん, and the occasional playful teasing from his older sister, 姉ちゃん. But when his older brother returns home for a while—having recently given birth to his second child—the dynamics of the household shift. With his brother's wife, the mother of his siblings, back in the house, the atmosphere becomes more intimate, and Taku finds himself drawn into a whirlwind of seduction and temptation.
The once-quiet home now buzzes with energy, especially when his sister returns, bringing with her a new level of allure. Taku can't help but notice how the familiar presence of his sister now carries a different kind of charm, one that stirs something deep within him. As days pass, the tension between them grows, and the simple act of sharing a drink or a moment of closeness turns into something more. His sister, once a carefree presence, now seems to be playing a game of her own, teasing him with every glance, every touch.
The household becomes a stage for playful encounters and moments of intimacy, with Taku caught between his affection for his sister and the growing sexual tension that fills the air. His parents, ever watchful, seem to know more than they let on, adding to the mix of emotions swirling around the house. The once-familiar routines of family life now carry a new, seductive edge, making every interaction more intense, every moment more personal.
As the days pass and the summer approaches, Taku finds himself caught in a cycle of desire and longing, his feelings for his sister growing stronger with each passing day. The home, once a place of comfort, now feels like a place of temptation, and Taku can no longer ignore the pull between them. The tension reaches its peak, and the familiar yet electric atmosphere of the household becomes the perfect setting for the culmination of all that has been building up.
