Niece Rina comes to her grandmother's house to deliver souvenirs from her father's business trip, as requested by her mother. She calls out to her grandmother after opening the door, but no one answers. While searching the house, she hears strange noises coming from her uncle's room. Peeking in secretly, she discovers him touching his cock. Curious about what he's doing, she asks, "Uncle, does it feel good like this?" and unconsciously starts stroking his cock with her hand, causing him to become instantly aroused. Encouraged, he pleads, "Let's do more~," and their relationship gradually escalates further...