The time is winter.
Koreimu and Komarisa are abandoned pet. Well, they are not badged pets, only those 500 Yen mass produced koyukkuri sold in petshops for those who just want to try raising yukkuri without spending lots of money for badged pets. Both are not sisters, but they are produced in the same time and got bought together. Both came straight from the production line. There's no parent or human who teach them anything about survival or how to behave.
10 days ago, they are bought by a kind mister. He always give them food and never scold them. 3 days ago, the Mister had enough and abandon them in the back alley.
He might not realize it, but that is a big act of kindness towards both koyukkuri. The back alley is a mess of trash, lots of food for rats, crows and strays. Both found home in old fish styrofoam box that is waterproof and well insulated. Nearby is exhaust from nearby building, keeping the house warm. For city strays, this is the best house where even koyukkuri can manage to survive the winter without much troubles.
But both of them lack parents and knowledge. Being spoiled, they know nothing of survival and have only the common yukkuri stupidity.
Koreimu think their new house is smelly (well, it smell like raw fish) so she want to look for her easy place, like the house she lived in where sweets sweets is always available. Komarisa who hesitate soon followed after hearing the promise of sweets sweets, leaving the house that would ensure their survival through this winter.
After running for half an hour, they jumped on the frozen asphalt in pain. Then as night falls, they hide behind the warm vending machine. For food, they only eat a little bitter grass growing nearby. Through the night, they ease each others by doing rub rub.
Next morning, they start looking for food. But without anyone to teach them, they don't know about scraping the trash. They can only asked. A kind human gave them chocolates and leave.
Both koyukkuri then starts begging more food from other passerby. Of course, most peoples are not so kind. Because of the successful first time, they think they will be able to do it.
So engrossed in begging food, they forgot to look for a new home and finally settle back behind the vending machine. But before that, a passing car splashed water on Marisa. The water quickly takes away body heat from Marisa. No matter how much Reimu tried to do rub rub, the next morning Marisa has frozen to death.
Reimu went out and asked for food again. Unlike yesterday, little by little she started to ask more politely. After being starved for so long, she no longer demand sweets sweets, just anything to eat is fine.
Finally a human offered food. He took her to an empty park and gave her sweets.
Then he torn her braids, pull off her peni peni, ruin her feet and take away her ribbon.
As she's left to die, Reimu has given up. She doesn't hope for anything anymore. Without braids and ribbon, she doesn't expect anyone would save her. She can't have children anymore so there's no point of living anymore.
She only doesn't understand why all these happened. Why the human do bad thing to her. Why Marisa died. What have they done to deserve this.
As she die, Reimu remembered her old house, the smelly house. It's so easy.