Maud Pie sniffed at the crack.
"Mmmm."
She peered over it cautiously.
"Ah."
With the utmost delicacy, she trailed a hoof down its length.
"Hrm."
Limestone Pie gave a low growl out from behind her, but restrained herself from jumping forward. "Well?!"
Maud Pie turned around, slowly lifting her gaze to match that of her sister's. "I have conducted a complete and thorough examination of the phenomenon to the best of my abilities."
"...and?!" Limestone demanded.
Maud let her eyes blink once.
Limestone frowned fiercely.
"....I have no flippin' clue what's going on."
Instantly Limestone reared into the air. "GRAAAAAAAH! Well I guess you're rockterate is just useless then!" She galloped away, harsh words spewing from her lips as she disappeared into the mine.
Igneous let out a small sigh, walking up to his daughter and awkwardly patting her shoulder. "I am sure thy sister means not what she speaks of thou. She merely expresses her frustration by pinning blame where she can, as ever."
Maud flicked an ear. "I'm not upset with her. I am upset that I can't figure out what this is." She pushed the hoof off, turning back to the crack and narrowing her eyes. "My special talent is the ability to discern details from what others would consider irrelevant. I've learned so much, both here on the rock farm and at the university. I should know what this is. I don't. That aggravates me to no end."
Marble wrapped her hooves around Maud's neck, gently nuzzling into her cheek. "Hmm."
Maud turned to her, a tiny smile on her face as she returned the hug. "...and you're still my sister too."
Igneous nodded to himself, smiling at his daughters held each other. True, they were the quieter of his progeny, but that also made their expressions all the more precious for when they did express them.
His eyes drifted to the crack, and his smile morphed into a frown. "I know for a fact that my ears did recollect the whistle of a train arriving but two minutes ago; moreover, twas the one upon which thine other sister proclaimed she would arrive. It is unlike her to spend so long at the station..."
Maud released Marble from her hug, giving her father a look. "She's probably just checking that mother is well. You know how Pinkie can get caught up in her own worrying."
"Mhm," Marble agreed, nodding emphatically.
"...perhaps I am worrying overmuch," Igneous conceded. "Dearest Cloudy did leave but five minutes ago. It is just... with such ill fortune to fall upon us, I cannot help but wonder after those of my kin that remain out of sight--"
The quick clip-clap of galloping hooves drew his attention to his rapidly approaching wife. More pertinently, her glasses were dangling from her neck, revealing the outright panic in her eyes. "Husband, daughters, attend quickly! Pinkimena hath brought upon us a dangerous boon!"
"She does have a tendency to do so," Maud deadpanned.
"Mhm," Marble giggled, covering a tiny smile with her hoof.
"This is no time for frivolity!" Cloudy Quartz insisted as she replaced her eyewear. "A princess even now approaches our homestead!"
Marble's laughter stopped abruptly as she stared wide-eyed at her mother. "Mmh?!"
"Surely you jest!" Igneous replied in disbelief.
"Nay, though I doubted mine eyes did not deceive! A pony of wings and horn was bespeaking with our wildest, and Pinkimena claimed friendship with her!"
Maud's eyelids fell to a lower position. "Did she have a purple coat?"
Cloudy nodded. "Aye, she did..."
"That'd be Twilight Sparkle then." Maud nodded. "I met her when I visited Pinkie before I went to the university. She really is a princess."
"MMH!" Marble shot up and galloped into the house.
"Thy sister is right," Igneous said firmly. "We must make haste to prepare our abode for presentation!"
"But dearest, would it not be crass of us to leave nopony outside for greeting when the princess arrives?"
"I'll stay out here," Maud volunteered. "She knows me."
Igneous nodded. "Very well. Come, dearest, let us move swiftly."
The two elder ponies trotted into the house as quickly as their old bones could take them. Maud watched them shut the door, her expression as calm and controlled as ever.
"...You can stop being invisible now."
There was a sound like a sigh, a shimmer in the air, and suddenly two ponies and a small dragon appeared beside her. The purple one let out a small sigh, giving a grateful smile to Maud. "Thanks for handling that so efficiently. I'm still not comfortable with the treatment some ponies think I deserve..."
"Or demand," quipped the dragon.
Maud glanced at him for a moment. Then she turned to the bouncing pink pony next to the purple one. "Who's he?"
"Oh! This is Spike. He's a dragon that Twilight here hatched when she got her cutie mark. Spike, this is Maud Pie, my older sister."
"The one that eats rocks?" Spike held out his fist. "Good to meet a fellow lithovore!"
Maud bumped the fist with a hoof. "Actually, everypony in my family eats rocks."
The pink pony sidled up to Maud. "Speaking of which, where are Marble and Limestone?"
"Marble ran into the house just before you got here. Limestone's down in the mine, working off some stress." Maud considered the princess for a moment. "By breaking crystals in half," she clarified.
Twilight nodded. "I gathered as much." Her eyes turned to the crack, and more specifically to the large rock that bore it. "So... this is the famous Holder's Boulder that Pinkie has told me so much about?"
"Yes," Maud said simply.
The three ponies and one dragon stared at the large rock for a few moments.
"...it looks like an egg," Spike stated bluntly.
"Spike!" Twilight admonished him. "This is the Pie family heirloom, and a center of their tradition!"
"He's kinda right though," Pinkie pointed out. "It does look like an egg."
"It is true," Maud agreed.
Twilight sighed. "Yes, I know, I just... didn't want to... you know, sound dismissive of something you considered so important."
Maud gave her an exceptionally flat look. "Pointing out facts isn't dismissive. It's investigative."
"Like if I pointed out this crack on Holder's Boulder, which was never there before!" Pinkie demonstrated eagerly. "Or how when I got the letter about the crack I thought 'gee whiz, that sounds almost impossible' and then I figured 'who do I know that does the almost impossible?' and then I said 'Discord, duh!' but then I thought 'I don't know if my parents are ready for Discord just yet or if he's ready for them' so then I decided to go with Twilight since she became a princess which is also pretty impossible you know?"
She suddenly frowned, tapping her hoof on the ground. "Wait, no, that wasn't investigative at all. Forget all that!"
Twilight managed to bite back a chuckle. "Right, well... I'm willing to help out in any way I can. Can you tell me what you know about this crack, Maud?"
"It started appearing yesterday at around midafternoon. After everyone living on the rock farm examined it, they sent out letters to me and Pinkie. I arrived this morning, and examined it myself. Despite my education in all things rock, I cannot identify a potential source. There is no impact indentation, but the crack is too constrained to be considered a form of natural rock expansion. The expansion of the lines are levered inwards, which is the exact opposite of what a chisel would provide." Maud paused for a moment, blinking as Twilight looked over the crack herself. "...If Holder's Boulder is hollow, something from within could have made this crack."
"First Spike says it looks like an egg, then you suggest that it might be hollow," Twilight quipped jokingly. "Next you're going to tell me that it was found in a cockatrice nest."
Pinkie giggled. "Ha, no, that would be silly! Holder found it in a dragon's nest." She pulled an old, tattered book out of her mane and flipped through the pages. "See? Right here in the family book of fables, 'origin of the rock farm.'"
Twilight froze for a second.
Very very slowly, she let her eyes travel up the height of Holder's Boulder.
"...so," Spike said, "it looks like an egg, acts like an egg, and was found with a bunch of eggs."
"...Spike, I need you to stand next to the boulder for a second. I'm going to try a relative magic resonance scan, just to make sure that this is not, in fact, an actual dragon's egg."
With a shrug, the purple drake walked up to the boulder and struck a pose.
Twilight rolled her eyes, but kept whatever she was thinking to herself. Her horn lit up, magic spreading out first around Spike, then all across the large rock.
After a moment, it faded away.
"...well?" Pinkie asked brightly.
"...It's a dragon's egg alright," Twilight conceded. "But it's a lot bigger than any dragon's egg I've seen..."
"Why is it only hatching now?" Maud asked. "It's been on the farm for generations."
"Hmmm." Twilight began to pace. "Well, I know from my experience with Spike that dragon hatchlings remain in a form of natural stasis until a large amount of magical energy is directed into their bodies, and I suppose that enough of Rainbow Dash's first sonic Rainboom could have been absorbed--no, but that was years ago... maybe it triggered a magical acclimation without internalizing the resonance--" She turned to Pinkie. "Didn't you say Applejack accidentally knocked it down into the mine?"
"Well, it's a biiiiiiit more complicated then that," Pinkie hedged, "but it did end up near the mine, yeah."
"Crystals." Twilight clicked her hoof against the ground. "That's gotta be it. Some crystals hold magical energy for a long time, so being near the crystals triggered the wakening process. That's the best theory I've got, anyway."
Maud glanced at the crack again. "If it took so long to start hatching, it'll probably be a while yet before it comes out."
"Yes, you're right. We should have time to make a plan about this."
"We?" Pinkie asked.
"Yes, we." Twilight brought herself up and started trotting quickly toward the house, the other ponies and dragon quickly following after her. "As much as this situation affects your family, the fact is we are talking about a dragon egg hatching in Equestria, which kind of involves politics. So I'm going to have to get involved, since I'm the closest political figure to the situation. Thankfully, though, we should have a couple of days."
Maud opened the door for them. "Assuming no more magic crystals get near it."
"Yes, assuming that." Twilight stepped aside so Pinkie could bounce in. "But the odds of that happening are almost--"
A sudden panting sound caused them to turn around, and they caught sight of Limestone dragging a cart full of pinkish crystals up the ramp. It took her a couple of seconds to spot them, but once she did she scowled. "What?! I had a lot of frustration to work out, okay?!"
With an audible crunch of rock, the crack jumped halfway up Holder's Boulder.
Limestone whirled, ears perked. "Oh no!" She rushed for the large object, cart still attached to her back. "Hang on, I'm coming!"
Maud flinched as the crack branched out. "Well, there goes our spare time."
"GET THE CRYSTALS AWAY FROM IT!" Twilight shrieked. "THE CRYSTALS ARE MAKING IT BREAK FASTER!"
Limestone spun around. "WHAT?!"
The cart, moving by inertia, spun next to Holder's Boulder. One of the crystals flew out, spiraling through the air too fast for Twilight to catch with her magic. As Limestone turned to look behind her, the tip of the crystal bounced against the crack.
There was a moment of tension.
Then Holder's Boulder exploded.