"The idea came from something I read in the newspaper about some cats being abused by strangers," says Janessa, 14, who studies at Australian International School Hong Kong.
Her entry took first place in this summer's Young Post short story competition.
Janessa says she has read many newspaper articles about animal abuse and they make her very sad. "There was this stray cat whose leg was broken by someone and a kind person took it to the vet. I think it's so unfair that animals are treated badly in Hong Kong," she adds. "And usually the cases are reported only after the animal has been killed or hurt. I do wish the police could do something to stop it from happening."
Janessa loves reading and enjoys fantasy novels the most. "Fiction takes me to another world," she says. "I can see the perspective of the author."
She has been telling stories to entertain her family since she was a primary school student. "I'd start my stories with, 'Once upon a time', and make it up all the way through," she says.
In real life, Janessa has never kept a cat - only some fish. But she used her imagination to create the main character - a seven-year-old "alpha male" cat, which lives on the dirty streets of Sham Shui Po.
"I wanted a distinct character. I wanted a 'cool cat' that was clever. He's a leader who takes care of his peers and makes sure they're safe."
Her story is written in the first person - or first cat - and told from the feline's perspective. Janessa says this was a deliberate choice. "When I see a cat or a dog, I've always wanted to know what he or she is thinking or feeling. It's an interesting puzzle to me," she says.
"Telling the story through the cat's eyes means I could give it a voice."
Janessa says she found it difficult to add details that would attract readers, and introduced the serious issue of de-sexing animals. "From what I've learnt, this is one way to stop the population of stray cats from growing," she says.
"To try to make it interesting, I looked at it from the perspective of the animals and imagined how they might feel about not having babies."
She chose the appearance of an animal murderer as the climax of the story - just what has often happened to cats in real life.
Janessa also introduced another character into her story - a human, called Anna, who is keen to help stray cats. "Anna is a Chinese woman from the animal shelter. She gives food to stray animals and takes care of them. There are many people like her in real life. We should praise such people for their efforts."
This is Janessa's first win in a writing competition. She credits her school's writing club, run by teacher Jackie Byrne, for her success.
"Miss Byrne encouraged us to enter the writing competition," she says.
"I've learnt how to write better by being in the club and I enjoy sharing stories with the group."
Janessa says she tried to give her story a meaningful ending - including changing the attitude of her alpha cat towards humans.
"I want people to think about the issue [of animal abuse] and to know that we can do something more to help stop it."