Chiharu is 28 years old, married for 5 years, with no children, half American and half Japanese. She was a cheerful and cute girl who was liked by everyone since she was a child. She had her first boyfriend after entering high school, and it was around that time that she experienced sex. She dated about 4 people, but in the end, the man she ended up marrying was the one she had never experienced before. She continued to live an ordinary family life for a while, but about 4 years later, she found out that her husband was cheating on her. Chiharu didn't dare confront him, but instead chose to play around to spite him... and then she met an older man...