As I have no knowledge of 'little sister a novel', it's impossible for me to describe its plot. You might consider reaching out to book clubs or groups dedicated to reading and discussing novels. They may have members who are familiar with this book and can share insights about its plot.
A possible plot could be that the tall little sister is constantly teased at school for being taller than the boys. But then she discovers her talent for volleyball. Her height gives her an edge in the sport. She joins the school team and leads them to victory in a big tournament, winning over her classmates and the bullies.
In the 'little sister muscle story', the little sister could be part of a group activity where everyone is encouraged to build their physical strength. She might initially be a bit shy or self - conscious about her small frame. But as she starts working on her muscles, she gains confidence. She could learn new exercises from her friends or an older sibling, and as she progresses, she not only gets stronger physically but also becomes more self - assured. This story could also include how her new - found strength helps her in other aspects of her life, such as being able to carry heavy school books more easily or helping around the house with chores that require physical strength.
Maybe it could be about a little sister who accidentally shrinks due to a magical spell. Then she has to face all kinds of challenges in a world that has suddenly become huge for her, like trying to get back to her normal size while avoiding being stepped on by the family cat.
Perhaps in a shrinking little sister story, there's some sort of scientific experiment gone wrong in the house. The little sister is caught in the blast and shrinks. She has to communicate with her family in creative ways since they can't immediately see her. She might use her wits to get their attention, like making tiny fires to create smoke signals. In the end, her older brother, who is a science whiz, figures out how to reverse the process.
It could be about Tenten's sister's adventures in the ninja world. Maybe she discovers a new jutsu or goes on a mission with Tenten and their friends.
It could be about her growing up on Pandora and learning the ways of the Na'vi. Maybe she has a special connection with the nature there that no one else has.
Maybe the sexy little sister is an artist. She creates beautiful paintings that are full of life and passion. One day, a famous art collector comes to town and stumbles upon her work in a small gallery. He is so impressed by her talent and the way she expresses herself through her art that he decides to sponsor her to have her own solo exhibition in a major city, which launches her art career.
One plot could be centered around a family secret. The big sister discovers that she is part of a long line of women who can grow to a giant size. She has to keep it a secret from everyone, including the little sister. However, one day the little sister accidentally finds out. At first, she is scared, but the big sister explains everything. Together, they use the big sister's ability to help their community, like saving it from a flood by building huge dams in her giant form.
Well, one possible plot could be that the little sister discovers a magical item that makes her grow into a giantess. At first, she's scared and confused, but then she realizes she can use her new size to protect her family and the town from a big threat, like a huge monster. She uses her strength and size to fight the monster and becomes a hero in the end.
Well, it could be about the main character having a really crazy day babysitting their little sister. Maybe the sister gets into all kinds of mischief like painting on the walls or trying to feed the dog chocolate. And the babysitter has to figure out how to deal with it all while also trying to have some fun with her.