"Catch me! Catch me!" yelled exuberant Anna happily. Elsa smiled, and rose another snow tower. Anna sped up, going faster with her jumps. Elsa started to panic. She couldn't keep up.
"Anna slow down," she called worriedly. Anna just giggled and jumped all the struggled to keep up. Suddenly, her foot slipped on the ice. She saw Anna jump again, and in fear, rushed her next ice blast. Elsa felt a rush of horror as it hit Anna, knocking her unconscious.
Elsa rushed to her side. "MAMA! PAPA!" she cried. "I'm sorry Anna," she whispered. Her parents rushed Anna to the magical trolls. Elsa cried and hoped that the trolls could heal her little sister.
The trolls erased all memory of Elsa's powers from Anna's mind. Elsa was panic stricken But... the protest died on her lips, unspoken. If Anna would be safer without Elsa in her life, then so be it.
That night they moved Elsa into a new room. Elsa knew this changed everything. The staff and everyone already called her a freak. Now that she had harmed Anna, and she couldn't see Anna anymore, the name calling and cruelty would only get worse. Especially without Anna to protect her.
Elsa missed Anna more than anything else.
She would often hear Anna ask. "Where's Elsa?" "Why isn't Elsa joining us?" "Why won't Elsa play with me anymore?" A cold frost started to bloom in her chest. Every time Anna talked through the door to her, and she couldn't reply, it hurt her heart.
A few weeks later, she looked outside her triangular window. It was snowing! Anna seemed to realize it too, because that morning she knocked on Elsa's locked door.
"Do you wanna build a snowman?"
Yes
"Come on, let's go and play."
I would like that.
"I never see you anymore."
That hurts me too.
"Come out the door"
I would if I could, but I can't.
"It's like you've gone away."
All happiness went from Elsa at that moment, and the frost started to slowly cover her heart.
"We used to be best buddies. And now we're not."
I'm sorry Anna.
"I wish you would tell me why."
She can never know.
"Do you wanna build a snowman?"
Yes.
"It doesn't have to be a snowman."
I'm sorry for what I have to say next. "Go away Anna."
Elsa could hear the deep sadness in Anna's voice from behind the door. "Okay... bye."
The cold frost periodically covered more of her heart. By the time Anna had sung a lot more, it had almost covered about two percent of her heart. Years later, her parents left on a trip.
"Do you have to go?" Elsa asked, heartbroken. The only three people who cared about her were her parents and her little sister. Everyone else called her a freak and struck her when her parents weren't looking or weren't around.
Her parents ship left, and Elsa was left with a still pleading Anna. Worry grew as no news came from her parents. Then a lone survivor from the ship arrived, bearing terrible news. Her parents and all the crew were dead.
Elsa didn't show up at the funeral, but Anna did. Anna decided to try one last time to get Elsa's attention.
"Elsa? Please, I know you're in there."
Anna…
"People are asking where you've been."
Probably so they can blame the death on me.
"They say have courage, and I'm trying to."
Be strong Anna. A plan started to form in Elsa's mind.
"I'm right out here for you. Just let me in."
It won't be long Anna.
"We only have each other. It's just you and me."
We only ever had each other.
"What are we gonna do?"
Leave it to me.
"Do you wanna build a snowman?"
...No
In that moment, the frost surged and covered half of Elsa's heart. Anna no longer came to visit, giving up on trying to communicate. Elsa was left in her icy isolation. She started to plan. She couldn't come out of her room yet. It was her parents last orders that she stay. But she would be of age in three years.
It would happen in three years. Her bitterness overcame her. She had no one who cared about her. Her parents were gone and Anna no longer came. She would make everyone pay. Everyone who mocked her, called her names, beat her. She had to make sure Anna didn't get caught in the crossfire though. Anna was the only person Elsa cared about.
In the three years before her coronation, Elsa planned and grew hardhearted. By the time her coronation came, the frost had covered three fourths of her heart. She had her plan. On her coronation, she would freeze Arendale, go to the North Mountain, come back, and kill everyone. Everyone, that is, except Anna. She would spare her sister.