note: I wrote this on my RP account on tumblr for the meme "Send me that symbol and my character will babysit yours". Guess I got a little carried away with it.
I'm still improving my English, but I hope you can enjoy this if you decide to read it.
Not beta-read.

Anna didn't know what to say when her parents were to sail to Corona.

"Look after your sister" they had ask her.

Not that she was against this, but the older princess knew it would be a challenge. Indeed Elsa was a polite little girl, that Anna loved from the bottom of her heart, but she was also quiet and reserved, what Anna admired about her. She was everything people had expect from her as the princess but that little girl mastered these abilities from her birth on unlike herself.

The first days were easy. They played, had meals together and Anna read her bedtime-stories every day.

"Anna?" Elsa's curious voice yawned shortly before she drifted to sleep. "When are Mama and Papa coming back?"
The older sister smiled, stroking the hair of the other one. "I'm sure they'll be back soon. Don't worry about it. They'll be back before you know it."

But she didn't know at that time that it was a lie. The days went by and Elsa withdrew more and more from the outside world, till she didn't even come out of her room anymore.

"Elsa? Please, open the door."
"Go away, Anna…"
"N-No, I won't. Why don't you talk to me?"

Anna didn't know when or why it happened that she sat half the day in front of Elsa's room, waiting for the younger one to come out, who'd hopefully had a smile on her face then. But that only happened in her imagination and times she dozed off, seeing the things she wished in her dreams.

"Elsa?" she asked again, knocking on the door. "You need to eat something. How about ice cream for dinner? You love ice cream, don't you?" Bribery was a low try, Anna admitted that, but she'd do anything to get her out of her room.
It was useless, she didn't even earn a response at that.

A deep sigh escaped the princess' lips when she rose to her feet. She leaned her head against the door, what became something like a ritual to say good-bye for the night.

The castle became a lonely place in a short time. There was no laughter, no singing or playing around anymore.
In addition to that the message of her parents' missing came the next morning.
"They never reached Corona's harbor."
Her eyes widened in shock and she dismissed the whole personal for the day, except the ones that wouldn't approach her anyway.
She didn't know how to handle these news, much less how to tell Elsa about it. Their parents were missing. What would that mean to them? How great was the chance to be found and come back to them in good health? Tears dwelled in her eyes at these thoughts.

No, don't cry, Anna. You need to be strong. You need to be brave for your sister. I am strong…

… but I'm also afraid.

15 minutes. That was all the time she needed to pull herself together and stand outside Elsa's room. The door looked like any other day, closed, unmoveable. She bit her lip, knocking once more.

"I need to talk to you."
Silence.
"Elsa, you will open this door. Now."
"No, I won't." Her voice sounded fragile and raspy, like she did cry, too.
"If you won't open it, I will" she warned. Any other time these words would be a complete joke. How would the little form of Anna break open a massive castle door? However, it wasn't. So she stepped back to take a running start and crushed into the door.

"Ou…" she moaned, but did it again, stubborn as she was.
"Anna? Stop it! You only hurt yourself!" Elsa cried behind the door "J-Just leave me. Please!"
The sound of someone stumbling against the door one more time made her twitch.
"A-Anna?" Elsa stuttered, her hands rested on the doorknob, tempting to open the door.

"Elsa, I already told you, I won't leave you alone" Anna laughed with pain in her voice. She didn't laugh about Elsa, but about herself. Her stubborness that everything she did, no matter what, was still in vain. How could she be responsible for an entire kingdom if she didn't get through to her only sister?

A quiet click announced the door opening before Anna, who still leaned against it, fell to the floor.
"What are you doing? Foolish, big sister…" Elsa scolded her, tears running down her cheeks. She made a move to hug her, but pulled back last second.

Anna forced a little smile, to assure her: "I'm okay."
But the little one shook her head. "No you're not. You really have the habit of running into danger." With these words she opened the door wider, showing the iced room. Anna's words fell silent, watching the snowflakes floating in mid-air. How was this possible? It was September and the sun shone outside!

When she finally got her voice back, she pulled Elsa, who was still crying and scared into her arms, holding her tight.

"I promise you, there's no need to be scared. I'll pull you through."
She would find a way to help her. With or without their parents.
After all that was an older sister's duty.