Lumina hadn't seen it coming at all.

She'd decided to investigate the tower on her own after Katrena had refused to let her go up there with the guards. But her father, mother and Fergis, for some reason, were all allowed to come (Fergis had declined). Even Aunt Scylla, old as she was, had been given the okay. But Lumina's mother didn't like to leave her out of her sight, and her father, though he tried, was still very protective. King Nereus had convinced his wife that Lumina should be able to go into the city whenever she wanted, but he always wanted her home by nightfall.

What did they know, though? Lumina had survived a swim through the collapsing skeleton of a sea beast, escaped a dungeon on her own, and taken down Caligo singlehandedly. Her parents should've known how capable she was of protecting herself. Only Aunt Scylla seemed to believe she was.

She was prepared to encounter Caligo or his eels in the tower. She was prepared to face sharks or other monsters. She was prepared to face a mean stonefish.

What she never thought she would see was a human woman looking through one of the windows.

Lumina heard a very muddled shout as she entered the tower's topmost room completely, and turned to see where the sound came from.

When she saw who it was, her mouth had fallen open in surprise.

It was a woman – a very beautiful woman. She had blonde hair a shade lighter than Lumina's, and it was in a single braid that fell across her shoulder. Her eyes were big and icy blue. And she wore the most beautiful gown. It looked like it was made of water somehow.

Lumina swam up to the window to get a closer look. The woman wasn't a mermaid – she was human. Lumina had never seen a human before, but she knew they lived above the water and had two legs instead of a tail. The woman had to be human. She wasn't floating, which meant that wherever she was, it was above water. And though her gown came all the way to the floor, Lumina could see shapes beneath it that certainly were not those of a mermaid's tail.

"Who are you?" Lumina asked.

The other woman said something but Lumina couldn't hear a sound.

Lumina knocked on the window. If she broke it, could she get to the other side?

The woman suddenly shouted something. A lot of things. Lumina couldn't make out words, but she could hear the muffled panic in the woman's voice. Why –?

Then she remembered. Humans couldn't breathe water.

If Lumina broke the window, she would probably send the whole ocean into the other side.

"My name is Elsa, Queen of Arendelle," Elsa had replied to the mermaid's question. In response, the mermaid had started banging on the window.

Was she trying to break it?

"No! Stop!" Elsa shouted. "You can't! The ocean will come in and drown everyone!"

The mermaid withdrew her hand with a guilty, "I-should-have-known" look on her face.

Elsa sighed in relief.

"Who are you?" she asked.

Lumina saw the woman let out a sigh.

She looked up. The woman was speaking to her again, but Lumina couldn't hear words.

"Who are you?" Elsa asked again.

This time, Lumina kept her eyes on the woman's face. She could make out the words Who are you?

Lumina didn't want to try to say anything, because she didn't want the woman to misunderstand what she said, given that Lumina thought she probably could only read her too and not hear her very well.

She summoned pearls from the shell she always wore and spelled it out, one word at a time.

Elsa watched as the mermaid bent the pearls to her will, arranging them into a word.

"Lumina."

Before Elsa could think about anything else, the word "Lumina" rearranged itself into a new word: "princess." Then "princess" turned into "of," which turned into "Seagundia." After "Seagundia," all the pearls flew into a shell the mermaid was wearing near the top of her tail.

Elsa guessed that this meant Lumina hadn't heard her name, if Lumina hadn't said hers out loud. She would need some parchment…

Then she remembered her ice powers.

Elsa made words out of ice.

"I AM ELSA, QUEEN OF ARENDELLE."

Elsa saw Lumina gasp.

Lumina was astonished. She had never seen such a thing before.

That was frozen water. She knew what it looked like; in the winter a sheet of it covered the ocean's surface, so no one could go above. This woman, Queen Elsa, seemed to have the same powers over water as Lumina did over pearls.

How could she be over there? There was no room beyond the window, just the outside of the castle tower. And somehow she was above water, but the tower was completely submerged.

It had to have something to do with the whirlpool that had hit the castle.

She did know that she couldn't very well communicate with Queen Elsa this way. She wanted to meet her and talk to her properly; it was the only way of figuring out what exactly was going on.

She formed her pearls into the words "I'LL BE BACK," then swam down the tower and towards the ballroom. She had to tell her parents about the phenomenon.