A unicorn in a white lab coat walked through the halls of the castle of the Crystal Empire. His face was stoic and calm, but his rushed movements and tensed posture drew more than a few glances. He navigated the halls quickly without pause and arrived at the Throne Room, where he was admitted inside. He trotted down the faded pink carpet until he reached the Crystal Throne.

“Princess Cadance.” The pony bowed low. “I have the results you requested.”

Cadance cringed at the look on the pony’s face. “How bad is it, Doctor Endo?”

Endo’s ears drooped. He hovered the clipboard over so she could see. There was a fair bit of technical jargon on it, but the flatline on the graph told Cadance all she needed to know.

“Zero?!”

Endo hung his head. “A powerful hatred-based curse has been cast on you. Conception will be impossible until it dissipates. I’m sorry, but for all intents and purposes, you’re completely barren.”

Cadance closed her eyes. She took several deep breaths, trying hard to keep her face from twisting.

“Sombra…”

Endo nodded. “I’m afraid the magic signature matches his to the letter.”

The throne room rumbled, the air around Cadance thickening into a pink haze. A corona of white light formed around her eyes as she fought not to scream.

Endo took a step back. “Your Highness…”

Cadance growled. The rumbling and haze died away, but when she spoke again, her voice echoed with barely restrained power.

“This isn’t fair,” she whispered.

Endo fiddled with his hooves. “I’m sorry.”

Hmph. Sorry wouldn’t let her have a foal, but she kept that comment to herself. “Is Shining Armor affected?”

Endo gulped. “A-Actually, there’s a b-bit of good news there! Our tests show that the Prince Consort is completely healthy! No abnormalities of any kind. This leads us to believe that the effects are not contagious.”

Cadance let out a heavy sigh. “Thank Celestia for that, at least…”

Endo shifted back and forth. “I, um... have to return to the lab now, but if I might be so bold, I’d advise you to inform Equestria of this. There are too many involved for it to be kept a secret for long, and I imagine your aunts would prefer to hear about it from you.”

Cadance slumped down in her throne. “Thank you, Doctor. You can go.”

Doctor Endo bowed, then turned and left the throne room. As soon as he left, Cadance groaned and lowered her head into a facehoof.

“It never ends, does it?”

Cadance sat alone in the ancient archives beneath the castle with her nose buried in a book with a green and red eye. To her left was a teetering stack of ancient tomes three times her height, and to her right was a massive pile of scrolls.

“Ironic,” Cadance muttered. “The bastard did research on love so he’d know how to fight it. Heavens above, this is supposed to be my special talent and even I didn’t know some of this!”

The Mad King Sombra had been a lot of things: violent, tyrannical, sadistic, power-hungry, devious… brilliant. His notes were methodical and detailed, building off of base concepts and formulas that even left Cadance scratching her head. It was depressing to think how much good he might’ve done had things been different.

Cadance pounded the table and groaned. Not for the first time, her thoughts turned to sending word south for help. Endo had been right that Celestia would inevitably hear of this, but Cadance wanted to at least try to solve the problem herself before getting others involved.

“I’m not going to run home crying to Equestria at the first sign of trouble.” She got up and stretched, then trotted over to a nearby chalkboard. “I’d never live it down if there was a simple solution I overlooked.”

Cadance took a few moments to recall all she understood about the curse that’d banished the Crystal Empire for a millennium, filling in the gaps with what she’d just learned from Sombra’s journals. Once she had a decent picture in her head, she started writing out diagrams and equations, intent on coming up with a counter-curse.

“All right.” She took a deep breath. “Let’s take this from the top.”

Hours went by. She quickly filled up the board in tiny font, then abandoned it and switched over to parchment. She filled up over a dozen pages in no time at all, all the while cross-referencing Sombra’s journals with her own knowledge of Love magic. She came up with a few ideas, most of them centered around the idea of undoing the damage already done, but she quickly realized that wasn’t going to work..

“There isn’t a single thing here that so much as mentions infertility!” Cadance shouted. “Either he didn’t write it down, or this is a side effect to something else he was trying to do! ERGH!”

Her head hit the desk with a dull thud.

…

Silence reigned as the candles around her burned.

…

“This is like grasping at vapors,” she mumbled into the wood.

Cadance stayed like that for a few minutes, miserable and fatigued. She’d been at this for so long already and had almost nothing to show for it...

...then, as she sat back up and scratched her stomach, she suddenly got an idea.

A ludicrous, silly, absurd idea.

“Snrrrk...” Cadance grinned. “Now that would be funny! I’d almost pay to see that…”

But yet the idea remained stuck in her mind. She continued think about it for a while longer, and amazingly, she realized that maybe, just maybe...

Cadance drew out some formulas, did a little bit more research, then picked her brain for a hole in her reasoning. All the pieces were in place, all the necessary players were in their positions, all the required components were readily available. It was just a matter of setting it all up.

Cadance stared at the parchment before her. “This… this might actually work.”

She sat up straight as the implication of those words hit her.

“It might work!” She threw up her hooves and cheered. “It might work, it might work, it might work!”

Cadance danced in place, spinning around and laughing. This was it! The answer she was looking for! She’d just had to think outside the box!

She chuckled as she put away her notes and headed out of the archives. She’d keep looking around for something a little more proper, but if nothing else panned out, then this really could be a potential solution.

Yes, if nothing else, this was a viable Plan B...

...so long as Shining agreed to do it.