Age
19
Jun Onoda (小野田 淳 Onoda Jun) is the 17 year old (currently 19 years old) daughter of Mamoru Onoda and Akiko Onoda and the younger sister of Akira Onoda and Makoto Onoda who initially has a rather romantic look on a relationship, and her quest for true love lets her drift through a number of affairs before she finally finds happiness with her first boyfriend, Yosuke. Her experiences and introduction into the sexual world are followed throughout the series.

Step Up Love Story
Makoto and Yura Onoda are a newly-wed couple with zero sexual experience. Yura is a shy and naive 25-year-old woman whose good looks grab men's attention, something that she dislikes because she gets embarrassed very easily. Her husband Makoto is of the same age, but as opposed to his wife, he loves having dirty thoughts about other women. Physically though, Makoto is truly faithful to Yura. Both of them may be virgins, but now that they are married, they are ready to dive into the world of sex, "practicing" as often as possible. However, the world of sex is complex, so they need all the help they can get to find their way through it. Thankfully, their friends, acquaintances, and porn media lend them a helping hand.