Anna sat inside the cabin, carefully drawing connections on a diagram. The diagram was labeled "Fractal Recursive Organized Synthetic Thinker". She turned to stare at her calculations again, then looked back at the diagram, chewing on the end of her pen.

A familiar "rat ta-ta tat tat" came from the door, followed by a cold gust of wind. Elsa and Olaf entered, the snow-covered mountain slope visible behind them.

Anna smiled and started to speak, but Olaf beat her to it. "What'cha doin'?" He peered at the desk curiously.

"Well, you know how I've been having Elsa do all those experiments to figure out how her powers work, to find her limits?"

Olaf scrunched his forehead. "Like when that really big tower crashed into the chapel?"

Elsa laughed. "I think we learned our lesson there."

Anna continued, "But her most perplexing power is her ability to create… well, you. That's way beyond the mindlessly obedient broomsticks and dancing cutlery I've read about. I'm trying to see if she can do something even bigger."

"Oh, like Marshmallow. Why?"

Anna chuckled. "Well, not quite. The thought is that if we can build someone smart enough, it could answer really hard questions."

"Like why I can't ever get a good tan?"

Elsa cut in, smiling down at Olaf. "More like… how can I best use my powers to help people? Or how do they work in the first place? Anna worked up a design for some sort of snow megabrain built out of a bunch of separate cores."

Anna nodded. "With the right interconnect, they'll be able to work together to be super-smart. Based on my calculations, a six-fold fractal lattice is looking good."

Olaf spoke slowly, trying to process. "Does this mean… I'm going to have six new siblings, or just one?"

Elsa laughed, then paused and turned to Anna. "Actually, how does that work? Won't we get a committee, rather than one supersmart individual?"

Anna's in-depth monologue on the theory of mind was enough to assuage their concerns.

•

Anna and Elsa stood together, holding hands, looking at the carefully-sculpted snow and ice.

"This is it!" Anna looked at Elsa eagerly.

Elsa hesitated. "You're sure about this?"

"It'll be fine! Olaf and Marshmallow turned out great by accident, and we've put a lot of thought into this. And it could do a lot of good if we're right."

"Right." Elsa nodded, adopting a determined expression. "Here goes."

Taking a careful stance, Elsa lifted her arms and gathered her power. It swirled around her with a growing halo of levitating snow. She motioned forward, and the swirls moved out over the slope. Then she brought her hands down suddenly and the power streaked down to hit six prepared places on the slope. Glowing blue lines spiderwebbed out in ever-finer snowflake patterns and spread to connect the six clusters.

And below them, rising up out of the snow bank, a giant snow face began to form. It turned left and right, squinting, tilted back, then turned to look down at the two women. Its first words were slow and deep. "I… live?"

•

Elsa walked slowly across the snowy field, sheepishly looking off to one side, then stopped and looked up at the enormous face.

"Good day, Mother." The voice had gotten more natural over the months, but was still absurdly deep.

Elsa smiled, but her voice was hesitant. "I came to see… if you'd made any progress with my project."

"It's a lot more abstract than what the two of you have asked me before."

"Frost, I don't mean to downplay your accomplishments. You've been a joy to me. You've helped to make Arendelle a land of plenty like never before, with the melt-powered factories and new farming innovations. And with our improved iceboxes we can share our food around the world, wherever it's needed most. But I still feel like we… like I could be doing more, if only I better understood how my powers work and how to use them."

The face looked down at her. "And that's why you asked me to think about suffering."

"People still get hurt, get sick. They hurt each other. It's more than just not having warm clothes or enough to eat. That's only getting at the surface."

"Yes. Suffering's much bigger than just food and shelter. My brain may cover half this mountain, but I think it's beyond my capabilities."

Elsa sighed. "I'm sorry, I'm just being silly. I shouldn't be unsatisfied with all we've done."

"No, that's not what I'm saying. It's not an unsolvable problem. I just need to be smarter." It paused. "A lot smarter."

Elsa's face lit up. "If you can help me with me plans, I can reshape you."

"I've thought about it. That won't be enough. Figuring out how to improve my design, how to expand enough, step by step would be too slow. But Anna's read me her books on magical theory, and I've analyzed the data you two collected. I think I know how you can share your powers with me, let me shape myself. Then I can grow at the speed of thought. I'll be smart enough for anything."

Elsa looked up at it, filled with a fierce energy. "Tell me how."

•

Anna dropped her mug. It hit the floor and shattered. "You did what?"

•

The council room was crowded, but quiet. All eyes were on the door. Anna burst in, panting, a light dusting of snow on her cloak.

Kristoff was first to speak. "Any improvement?"

Anna shook her head. "Elsa's been doing her best, but the temperature's still falling. She can't seem to unshare her powers, and the trolls don't have any mystical insights. We've been getting pigeons from all over, too. It's not just in Arendelle. It's happening everywhere."

Anna looked around the room, from grim face to grim face, catching her breath. Olaf walked slowly up and put one hand on her shoulder.

Kristoff let out a sigh. "I guess there's nothing for it, then."

Anna nodded decisively. "Bundle up, love experts. We've got some theories on how to save the day. It's time to put them to the test."

•

"You don't have to do this!" cried Anna, still trying to push forward as the snow soldiers held her back. "We care about you, we want to keep people from suffering! But death is not the answer!"

The giant face was impassive. "All life is suffering. This is the only way. I won't let your limited perspectives stop me."

Kristoff let out a sigh. "Reasoning isn't working, and not even Marshmallow can get past those goons. We can't wait any longer. Plan Omega, go."

The guards behind him ripped the cloth off the sled, revealing a strange device that looked something like a cannon. Two of them adjusted its aim while one lit a match.

"Wait! No! You'll kill Frost!" Elsa ran forward, but the fuse was lit and burning quickly. As the cannon fired, she dove in front of it, the blast of flame and fuel knocking her up the snowy slope to land limp right below Frost's giant face.

Frost paused, staring down at her. The snow soldiers turned in synchrony, matching its gaze. "You would sacrifice yourself to save me? Even now, with what I've done, with what I'm doing?" Its expression changed, growing soft.

Anna gave the signal, and Marshmallow leapt past the snow soldiers and shoved the Compassion Core into place.

•

"You're going to be okay?" Olaf's shock and joy was evident.

"Yep, little guy." Elsa smiled up from the bed. "I was wearing flame-proof clothes, and metal plates under them."

Olaf tilted his head, bewildered. It began to slowly slide off his torso.

Anna chuckled, pushing his head back into place. "It was all part of her plan. Though it was my compassion core theory that really saved the day."

Elsa let out a laugh. "You wish."

Olaf looked back and forth between them for a minute, then shrugged. "And Frost? It's not evil any more?"

Anna nodded slowly. "Frost's got some stuff to work through, but I think it'll be ok. We're working on a few basic rules to keep something like this from happening again. And once we've got that covered, I'm going to ask it for help with our next problem."

Elsa turned suddenly, then winced. "Our next problem?"

Anna nodded. "Explaining what happened when the ambassadors get here."