"My girlfriend has no interest in sex at all. I thought I could stay over at her house this weekend and have loads of fun... But from the looks of it, I guess we'll just watch movies and play games..." Then, his busty sister, the complete opposite of his girlfriend, comes home. His eyes are drawn to Yuka, who is leaning forward and blowing air into her blouse with a fan. Then, Yuka takes a photo of him staring at her breasts, and...