A 22-year-old from Chiba Prefecture whose specialty is badminton. She graduated from university a year ago and started working at a local company. "I've lived at home my whole life, so I've never even masturbated," she says. Her first time with a boyfriend at age 20 was the only sex of her life. This is the complete story of a "nearly virgin" girl experiencing intense eroticism and becoming a "mature woman."