My two sisterly girls come to visit me at my new solo apartment. Among them are Erina and Ichika. Erina has always been a breast-obsessed little sister, clinging to me since childhood with a deeply affectionate nature. After graduating middle school, she confessed, "I... I love you, big brother," causing me to lose control and cross the line. Even after moving out to attend university and living alone, she visits me every weekend. Each time, she whispers, "I love your scent, onii-chan," deepening our intimate, loving bond. Meanwhile, Ichika is fiercely jealous and overly attentive. She comes to my Tokyo apartment during long holiday breaks. With each meeting, she gradually appears more mature, becoming aware of my growing desire. She constantly asks, "You don't have a girlfriend, right?" Worried about me living alone, her jealousy intensifies daily. When she finally says, "I love you so much, onii-chan," her innocent face transforms into that of a passionate woman. Drawn in by her bold advances, I give in completely. My connections with both sisters grow stronger, entangling all of us in a complex web of desire and emotion.