Prompt, my own headcanon: Anna's child will knock on Elsa's door and ask her if she wants to build a snowman all the time. The first time is quite unexpected. They get used to it after a while.

A small, persistent rap on the door drew Elsa out of her trade agreements. Elsa usually kept the door open. It was only ever closed when her work piled dangerously high. Her most frequent visitor was Anna, but this wasn't her usual quick three knocks and instant entrance (As the door was typically open, Anna only forced entrance under the most dire of circumstances. Things on fire, arguments with Kristoff, deciding the menu for dinner. Important things.)

Nor was it one of Olaf's spontaneous entrances, as he never bothered with knocking when he intended to enter. Neither did the sharp voices of the guards accompany the knocks - ruling out nine-tenths of her usual visitors. The knocking continued, soft and steady, as Elsa pushed back the great carved chair and crossed to the door.

The bare metal handle was neither cool nor warm to her touch, despite the early winter chill in the air. Elsa pulled the door back, blinking at the light from the picture window in the hall.

"Auntie Elsa!" the child bounced up and down. "It's snowing! It's snowing!"

True enough, snow - natural, non-magical snow - was falling lazily in the midafternoon sky. The grounds were already losing all color but white. The snow brought Elsa memories of childhood and mountain palaces, like it always did. But memories tempered by the last few years, so that they no longer tore at her and threatened to make her lose control.

"Yeah, it is," she smiled. "Where's your mother? You should go out and play."

"No, I wanna play with you, auntie!" The girl stamped her foot to emphasize the point. Elsa scanned the hallway. Surely Anna wasn't far away. Elsa couldn't bear to disappoint her child, but there was so much work before the week was out.

"I can't today."

"Why not?"

"I have to read over our trade agreements with Kristensand, and then the prince and princess of Corona are coming soon and there are many things to prepare-" the child crossed her arms, not actually caring for details of visiting royalty. Elsa quickly shortened the explanation "I'm busy today. I'm sorry."

"Just for a little bit!"

"No, I really can't-" A swish of skirts around the corner caught her eye. Anna peeked out from behind the wall. Elsa wasn't sure if Anna had put her daughter up to this or was just waiting to see the outcome. Either way, Elsa wasn't letting Anna stay out of it. "Look, here's your mama, she'll take you out to play."

Anna stepped out from her hiding spot, a little crestfallen. Clearly she had wanted Elsa to put aside the work for the afternoon. "Come on, Gerda. Auntie can play another time."

"But I want to play with-

"Gerda."

"Just for-"

"No."

"Just long enough to-"

"Nuh-uh."

Elsa covered her mouth, trying not to laugh at how much Gerda took after her mother. Anna picked the girl up, bouncing her in her arms. "Come on, let's get ready to go outside."

But Gerda stubbornly turned to Elsa one more time and pleaded. "Don't you wanna build a snowman?"

Those words hadn't been uttered in the palace for years. That dreaded night when they were kids. Knocking. Closed doors. A veiled portrait. Elsa, normally so composed and controlled, felt something almost like a physical blow. She attempted to reply, but could find no words.

Anna had a similar reaction, mouth actually hanging open at her daughter's question. The sisters looked from Gerda to each other.

"Did you-?" Elsa started to ask, did you tell her to say that? but from the look on Anna's face, she already knew the answer.

"Did you-?" Anna was just as taken aback.

Gerda, neither understanding nor caring what all the fuss was over her simple question, repeated herself: "Mama, auntie, do you wanna build a snowman?"

Elsa briefly thought of the unanswered missives on her desk, the trade agreements to review and approve, the pair from Corona due to arrive in a week, and- and-

Do you wanna build a snowman?

"Yes," Elsa found her voice, something like a smile starting on her face. "Yes we do."

Gerda raised her arms in triumph. "Yay!" Anna beamed, more excited than her daughter. They turned down the hallway. "Come on, let's go find your father and Sven and get a good carrot."

"Why do we need a carrot?"

"For the nose, silly! Don't you know how to build snowmen?"

Anna and Gerda's voices grew less distinct as they bounded down the hall to the kitchens and Elsa followed.

I almost feel bad writing Frozen fanfic because there are authors out there who do a much better job than I. (Anysia and thefireplanet in particular) But this idea was too cute and I had a long layover, so here you go.

"Kristensand" is borrowed from Halm Vendrella's "Frozen: The Snow Queen".