Maki is a single mother who is raising her son Taro, a high school student, after divorcing her husband. One day, Taro wins a trip to Okinawa in a neighborhood lottery, and Maki travels to Okinawa in his place as Taro is busy with club activities. A few days pass, and when Taro returns, he can't help but cry out. He has been tanned and his appearance and personality have become brighter than ever. Taro is confused, but Maki has him apply moisturizing cream, saying, "My tan is itchy." She takes her unsteady son's hand and gradually brings it closer to his private parts...