I don't own the Powerpuff Girls.
Blossom was a puppet.
She was far more gifted than anyone she knew, including her sisters. Bubbles could speak many languages. As Blossom grew older she learned those languages and could speak them fluently. Buttercup was strong. Blossom could defeat her strength with her mind. It was her intelligence and her mind that made them able to use their powers successfully and save the day. She had to take care of her sisters and help them improve, like she was their tutor. They were family. What else could she do? She couldn't not help them.
A string on her heart.
She didn't even need to compare herself to the citizens of Townsville, who were weak and idiotic. Their lives depended on her and her sisters. Without her answering the childish phone, without her listening to the Mayor's pleads, without her going to the scene of the crime, the city's citizens would be dead within a week. She had to beat up the monsters and villains. She couldn't let her city die because of her.
A string on her fists.
Then there were the Rowdy Ruff Boys. God, how she hated them. They went against everything she stood for. They hurt her sisters, they destroyed her city and they went against all the justice in her body. They were disgusting, stupid and brutal, yet they had the same colour hair and similar eyes. They both had superpowers. Everyone thought they were cute together. They ignored their conflicting beliefs and personalities. Everyone paired them up together because they thought that was what should happen.
A string on her future.
At school she helped her sisters learn. During the day she saved the lives of Townsville. Then at night she snuck out of the house to meet Brick, and they would kiss under a lamppost. He would touch her in places that she let no one else touch just because it was romantic and expected of them.
A string on her body.
She could see the strings attached to each of her limbs, controlling her and deciding every move she made. She could see the path of her life laid out in front of her. The strings pulled her along each pavestone. She was a puppet and she didn't choose what she did in her life. Her puppeteer did.
A string on her life.
PPGGPP
One day, Blossom broke those strings.
Her family woke up to find that she was not in her bed. She wasn't downstairs. She wasn't in the house. She wasn't anywhere.
Later that day, Mojo Jojo attacked Townsville with his new invention- a giant robot. The two remaining sisters didn't know how to defeat it. The robot killed hundreds of people before they found out its weakness.
That night, the dead body of Brick was found attached to a lamppost. His hands were cut off and his mouth had been sealed by something incredibly hot. This had suffocated him because he didn't have a nose to breathe from.
Buttercup, Bubbles and the Professor stood in a destroyed Townsville, clutching branches of cherry blossom. They picked off each petal and held out their hands. They blew them and watched the petals disappear into the distance.
They watched the petals disappear into the distance, standing on abandoned puppet strings.
Kodos to Kagami Rin Ne for pointing out some errors. The 'did' was a useless typo.