Naoyuki Shimoduru

Koguma is a high school girl in Yamanashi. She has no parents, friends, or hobbies, and her daily life is empty. One day, Koguma gets a used Honda Super Cub motorcycle. This is her first time going to school on a motorcycle. Running out of gas and hitting detours become a small source of adventure in Koguma's life. She is satisfied with this strange transformation, but her classmate Reiko ends up talking to her about how she also goes to school by motorcycle. One Super Cub begins to open up a lonely girl's world, introducing her to a new everyday life and friendship.

Ah, high school. Is there any better place to start fresh after a horrible middle school relationship? Nope! Not unless your ex ends up at the same school as you and is now your stepsibling. What was supposed to be a sanctuary of peace where I could avoid ever seeing her again has become a living nightmare! Everywhere I look, I see her—in my house, in my school, in my class. There's no escape! She even claims that she's the older sibling. Like hell she is! But I won't lose to her. After all, I'm the older brother in this new family situation. That's right, we're family now. No matter how much we may have thought we loved each other before, we saw one another's true colors and realized we weren't meant for each other. That's why even though we may keep up a buddy-buddy sibling act for the sake of our parents, things will never go back to the way they used to be.