Lyra slipped a hoof under her collar and tugged. Her maid outfit was too tight, but she couldn't grumble about it. It wasn't hers and Lyra wasn't in any position to have it altered.

Marble was trotting behind Lyra. There was a covered plate of food balanced on her head.

Lyra's mane was stuffed into an old-fashioned maid cap. She'd discovered the cap in a formerly locked supply closet. Supply closets in fancy hotels were especially vulnerable to experienced lock-picking.

“I hope this is the right room,” Lyra said.

If she'd been duped, Lyra was going to hunt down that maid and exact a fitting revenge. They'd had to bribe the maid to an absurd degree for the outfit alone. The information came at a much higher cost. If everything went down satisfactorily, it was worth the bits.

Parking the maid cart behind her, Lyra motioned to Marble.

Marble reluctantly approached the door. She quivered as she raised a hoof to the door. Marble knocked three times.

“R-Room service,” she croaked.

There was no answer.

Marble knocked again. When she spoke, her voice had a more confident air to it.

“Room service!” she said.

She heard nothing from the other side of the door. Marble had expected either the door to swing open or somepony to yell from inside that they hadn't ordered room service. But nothing stirred in the hotel room. It appeared to Marble that Fleur had indeed left the hotel, perhaps for a long dinner. Marble motioned Lyra closer.

Lyra trotted up to the door and put her ear against it. She too heard nothing. Lyra straightened up and nodded at Marble.

“We're going in,” she said.

Lyra pulled out the spare keycard she'd gotten from the maid. She swiped it across the reader. Lyra smiled as she heard a familiar click. She gave the unlocked door a gentle push and watched it swing inward.

Marble slipped inside behind Lyra. She closed the door behind them.

Lyra stopped, tensing herself. She was ready for anything, be it a blaring alarm or an attack. But the room seemed to be entirely vacant.

She stepped forward slowly, her eyes searching for trip wires or concealed explosives. The room looked extremely ordinary. It looked much like Lyra and Marble's room, except there was only one bed.

The room was noticeably cleaner. It had the familiar obsessive tidiness that was characteristic of most unicorns. Despite the room obviously having been used sometime in the past day, everything was in order. The bed was made, books were stacked neatly on the nightstand, and everything was spotless. Some unpacked luggage stood in one corner. The luggage bore Fleur's Cutie Mark.

Lyra started with the books. She flipped through each of them, but they all seemed straightforward. They were generic romance novels written by authors Lyra didn't know. There were no hollowed-out pages or suspiciously circled bits of text.

Marble searched the bathroom. She found various make-up products lined up neatly on the sink and some medication in the cabinet. Marble hesitated over the latter. She recognized the labels as various remedies for headache or stomach pains.

She picked up one of the bottles and shook it. It was empty. She picked up another bottle and gave it an experimental shake. That one didn't sound empty, but it also didn't sound as if it was filled with pills. Frowning, Marble popped the top off the bottle and peered inside.

Lyra was searching the closet. She pressed both hooves against the back wall of the closet. No secret compartment as far as she could tell. Perhaps there was something in Fleur's luggage. Lyra was hesitant to look. She didn't want Fleur to know they'd been in her room.

Marble came galloping out of the bathroom with the bottle.

“I found it, I found it!” she said.

Lyra trotted up to her and took the bottle. She analyzed it, confused. It looked like a common headache remedy. Lyra had seen it countless times over the course of her life. Curious, Lyra popped the top off.

Instead of pills, the interior of the bottle was occupied by a slip of paper.

Lyra's face lit up with comprehension. She pulled the paper from the bottle and unfolded it, her gaze dancing over the hoofwritten message.

Anomaly 63-C.

She frowned. Where had Lyra heard that before? In the notebook? In a book she'd read? For that matter, why had Fleur hidden it?

Lyra trotted into the bathroom. She emptied the cabinets in a rather hurried fashion. She had ceased to care if Fleur discovered evidence of her and Marble's snooping. As Lyra opened each bottle in turn, her mind surged with excitement. Lyra tried to dig out some buried memories. She was searching for some hidden reference to the mysterious “Anomaly 63-C”.

The remaining bottles were devoid of anything suspicious. However, Lyra didn't want to leave. They had found something of possible significance, but she refused to accept that alone. They'd taken an immense risk and Lyra wanted a grand payout.

“What haven't we checked?” she wondered aloud.

She idly tapped on the sink as she thought. Lyra's eyes drifted from the polished porcelain to the gigantic mirror above the sink. She stared at her own reflection, her head tilted slightly in thought. The mirror looked slightly odd to her, but she couldn't put her hoof on why. Lyra looked behind her, then back at her reflection. She squinted.

It hit Lyra so abruptly that she jumped. She stared in astonishment at her reflection. She dismissed it as some trick of the light for a moment, but Lyra soon realized it couldn't be. She experimentally raised a hoof and lightly tapped her maid cap. The action confirmed the oddity Lyra had noticed.

The reflection wasn't a reflection. While Lyra should have been mirrored, she wasn't. She was staring at herself exactly as she was, the image not reversed.

“L-Lyra?” Marble said nervously.

Lyra didn't hear her. She extended a hoof towards the mirror. She was quivering, afraid but driven by curiosity. Lyra's most prevalent fear was that it would be nothing. But in her heart she knew it would be something.

Marble gasped.

Lyra's hoof slid into the mirror, the surface rippling like water. A frigid sensation spread from her hoof to her neck. It was like she'd thrust herself partly into a pool of icy water. The cold almost bit into her fur. Lyra reached even further, more of her front leg disappearing into the mirror. Lyra was leaning forward, her head steadily nearing the mirror's rippling surface.

“Don't!” Marble said.

But when the tip of Lyra's muzzle touched the surface, it was inevitable. Lyra leaned into the mirror. Her head slid through the false glass. Frigid air raced from the top of her muzzle to her eyebrows. In an instant, Lyra's head had breached the world beyond the mirror.

She found herself peering into what appeared to be a library. There were shelves lining the walls and a few sensible chairs in the middle of the room. However, most of the shelves lacked books. They were instead filled with all kinds of items, ranging from broken toys to unidentifiable gadgets. Lyra's eyes were attracted to a beautiful music box sitting on a high shelf.

Marble was saying Lyra's name over and over, the urgency in her voice rapidly increasing. But her voice was distorted and therefore easy to ignore.

“A pocket dimension,” Lyra said in awe.

Lyra had read about magic like this, but she had believed it virtually impossible. Surely no unicorn was powerful enough to master such an intricate spell. Even the great unicorns of a lost age would have struggled with it. Lyra was thunderstruck and a little worried. Any unicorn capable of doing this was not a unicorn Lyra wanted to cross.

She levitated the music box from the shelf. It looked ordinary, but Lyra sensed magic within it. She flipped it over and examined the bottom. Lyra nearly gasped.

“For now you must follow the moon,” Zecora had said.

There was a crescent moon symbol on the bottom of the music box. Could that be what Zecora had meant? Was the music box special in some way? It certainly had a subtle aura of magic around it.

Lyra spotted something else. The only reason she noticed it was because it was one of the few books in the room. Lyra's gaze was drawn to it due to how out of place it looked. It was on one of the farthest shelves, but Lyra could see the cover. She instantly recognized it, her heart going into a frenzy.

It was a spellbook. But not just a normal spellbook one could grab at the local bookstore. It was the spellbook. Lyra recognized the symbol even from a distance. It was the spellbook Twilight had shown her all that time ago.

Lyra withdrew from the mirror with the spellbook and the music box. She was struck speechless by her good fortune. How had she never realized, never even suspected? Of course Fleur would have it. It needn't even be a copy. Fleur could have gotten it straight from Twilight Sparkle.

When Lyra could speak again, she turned to a bemused Marble.

“We're going,” she said.

Their vacation had come to a sudden end. They were getting out of Fleur's room, out of Los Pegasus, and hopefully somewhere far away from anypony trying to catch them. They had everything they needed, perhaps more than they needed.

“Where?” said Marble.

Lyra trotted out of the bathroom, Marble hurrying behind her.

“Anywhere,” she said.

Fleur was going to find out they'd taken the music box and the book. Her next move would be calculated. Whatever Fleur planned, Lyra doubted her and Marble would see it coming. With the spellbook in hoof, Lyra felt they were officially out of their depth.

“We need to find a library,” said Lyra.

First things first. They needed to find out about Anomaly 63-C.