It was a blissfully boring Saturday afternoon in Storybrooke, and Regina had taken the opportunity to give Emma a lesson in potions. Sure, they had been enjoying a reprieve from saving the town and its residents from any major threats for a few months now, but it wouldn't hurt to improve the Saviour's skills. Besides, it was nice for Regina to have someone to share her magical knowledge with and Emma enjoyed learning it.

The ladies were in Regina's vault, and Regina was rummaging in a large chest while Emma browsed an assortment of vials on a large bookshelf at the other end of the room. Regina was thankful for the stone walls cooling the room as she stuck her whole head in to the musty old chest to look for the particular book she planned on using for the lesson.

Emma paused as a small vial of silver dust caught her eye. "Unicorn horn dust?" she asked Regina incredulously.

Regina pulled her head up to call rather defensively, "That unicorn was dead when I found it!"

Emma shrugged, not bothering to press for more details as she was too fascinated by the various bottles and jars in front of her. They had peculiar labels like 'essence of manticore' and 'eyelash of dwarf', and contained a strange assortment of items. Such as something that looked to Emma like a piece of beef jerky floating in a vial of blue Kool-Aid.

A gorgeous little bottle of swirling iridescent liquid sparkled purple under the candlelight, and Emma curiously grabbed for it. She inspected the bottle, wondering if it was the bottle or the potion inside causing it's purple glow.

Behind her, Regina had located the book at the very bottom of the chest. It was a pretty basic potion brewing guide, so she hadn't much use for it in years.

"Aha! Got it!" Regina expressed triumphantly as she turned around to show Emma the thick leather volume. When she saw that Emma had taken the stopper off a little bottle of glittering purple liquid and was bringing it towards her face, she quickly said, "Wait don't!"

Emma shot her a look of amused annoyance and said, "Relax, I wasn't going to drink it, obviously."

But Regina sighed in frustration and responded, "You sniffed it, didn't you."

It was a statement, not a question, as the lavender smoke beginning to swirl around Emma had already made the answer clear.

Three seconds later, she was faced with a four or five year old little girl in very oversized clothes looking quite alarmed.

Emma looked down at her clothes and small body. The bottle she was still holding looked huge in her tiny hands.

"What just happened?" She managed hesitantly, then her eyes grew even wider at her high-pitched voice.

Regina sighed again and shook her head, then promptly took the potion from Emma and replaced the stopper. She carefully lifted the large ornate mirror off the wall next to her and said, "So, don't freak out, but..." she grinned sheepishly as she lowered it down to Emma's new height.

Emma's eyes bugged out of her head as she gaped at her reflection.

"This happened just from smelling a potion?" she yelled.

"That stuff is potent," Regina nodded, "but don't worry, it's temporary."

Emma was too shocked to respond as she stared at herself, but her expression grew relieved at the reassurance that it would wear off.

After a moment, Emma looked to Regina accusingly. "Why would you not have a warning label on that? And what the hell do you have it for, anyway?"

Regina raised her eyebrow, leaned the mirror against the wall, and showed Emma the little paper label tied around the neck of the bottle. It read, in Regina's cursive handwriting, 'Concentrated. Do not breathe vapours.'

Emma blushed and looked at the floor. "Oh".

"As for why I have it, how do you think I maintain my youthful glow?" Regina gestured proudly to her face. "I use a diluted version, of course."

Emma sighed. "So... just how temporary is this stuff? Will it wear off soon?"

Regina nodded. "In about twenty-four hours, maybe a bit less."

Emma's eyes grew wide again "Twenty-four hours! We have family dinner tonight! My parents can NOT see me like this! They'll get all... mushy." She screwed her face up at the last word. "Isn't there some way you can speed it up?" Emma whined.

Regina shook her head, trying not to laugh at her whinging like she was an actual child. "Not in twenty-four hours. I'd need to make an aging potion, and I'm not even sure I can source all the ingredients in Storybrooke. Plus, getting the dosage right would be risky. Better to just let this run it's course."

Emma groaned dramatically. "Gggreat".

Regina gave her a sympathetic smile. "As long as we're here, why don't we continue with the lesson? Just... don't touch anything else unless I tell you to."

She waved her hand and Emma's clothes shrunk down to fit her, then waved it again to produce a step stool next to the counter where they would be brewing the potions.

"Thanks," Emma muttered, an adorable pout on her tiny face.

A few hours later, Regina opened the door to Snow and David's loft and came partially inside. Snow and David looked up from the kitchen at her arrival, but before they could greet her Regina started talking.

"Now, before you freak out, this is completely temporary and I had nothing to do with it."

Snow and David exchanged a look of confusion as Regina fully entered the loft, followed by a downsized Emma. It took a second, but as they took in her blonde hair, green eyes, and miniature red leather jacket, they gasped in unison. "Emma?" Snow asked in shock.

Emma smiled nervously and avoided her parents' wistful gazes. "Hi Mom."