Ryoko lost her parents in an accident when she was young. The Hojo family adopted Ryoko, who had no relatives. Her stepparents were very kind, and her step-sister Maki also Ke'ai Ryoko like her own sister. A few years later, Ryoko, who had become an adult and was living alone, received a phone call. It was from Maki, who had divorced. That night, Maki came to stay over, and the demeanor was completely different from when they lived together. She suddenly touched Ryoko's body in a depressed state...