Well after the last echo had faded they stood in stunned silence, all of them waiting for someone else to break it. Derpy was the first. "Doctor, what do we do now?"
"We have to figure out the riddle. Where's someplace that ponies can't go?"
Everypony thought for a moment. "The ocean?" Twilight suggested.
"The moon?" Pinkie Pie added.
"That's a good start. Now tell me about Discord. What's he like? Where would he hide them?"
"Somewhere we could find." All eyes turned to Twilight. "It's just that last time it was in the most obvious place. He enjoyed beating us more than actually winning."
The Doctor grinned at the purple unicorn. "Excellent, Twilight. So we can get them we just can't get to them. That rules out any oceans and moons."
"And puts us right back where we started," Applejack pointed out.
"Correct."
"What we don't know is where he's capable of putting them. Depending on how much power it took for Discord to break free his powers could be limited." Derpy smile proudly as the mane six stared at her.
"You've done this before," the Doctor told her.
"Well duh. I'm your companion, remember?"
"Um, yes. So where was this chaos god held?"
"In the garden," Celestia told the Doctor. Twilight will show you. Everypony else, come with me. I have something special I need you to take care of."
"Yes Princes," they all chorused.
As Twilight came to a halt in front of the empty stone pedestal she asked, "So what exactly are we looking for?"
"Anything unusual," the Doctor replied. "Derpy, have you seen my sonic screwdriver?"
"Right here Doctor." The gray pegasus cheerfully tossed the screwdriver to the Doctor while Twilight tried to figure out where she'd been keeping it. She had just decided that some things were better left a mystery when there was a surprised shout from the hourglass stallion.
"Gah!"
"Doctor! Are you OK?" Derpy asked in full on panic mode.
"I'm fine, it just surprised me." He glared down at the smoking screwdriver on the grass. "It sparked. In my mouth."
"Ouch."
"Yes. I wonder..." He trailed off as he bent closer to the smoking device. Derpy let her eyes wander around the garden, one eye taking in every detail and the other fixed on the Doctor. "Was every statue here once a living creature?"
"Pardon?"
"If one statue was alive what if they all are? Maybe all of them are secretly living things and if we make the wrong move they'll come alive again and attack us!"
"I don't really think that's likely," Twilight said reassuringly. "And even if it were true I'm sure we're perfectly safe."
"Oh undoubtedly," the Doctor told the two mares. "It looks like only Discord was strong enough to break free from his prison, and that was just by chance. If I'm correct, and I always am," he cantered over to the pedestal, sniffed the air, and licked one of the stone fragments. "Temporal waves. Well, more like ripples actually."
"Temporal ripples?" Twilight asked. "What could have caused that?" Out of the corner of her eye she caught Derpy looking at the Doctor with a somewhat dreamy expression and filed it away in her mind for later. It was always good to notice small details.
"You remember how I said that I got to you before anything too bad happened?"
"Yes."
"I was wrong."
"Oh."
The Doctor galloped around the pedestal still talking a mile a minute. "As far as I can tell, Discord was held in some sort of quantum lock, removed from time with a thin stone casing around him. When you traveled back in time it caused ripples in the fabric of time and space. Normally this wouldn't be too big of a deal, but the ripples disturbed the quantum lock and he was able to break free."
The Doctor turned to look at the ponies and found them frozen with rather blank looks on their faces. He smiled and waited for them to say something. They didn't. He frowned slightly and looked around him. Everything had frozen. The wind, the birds, the branches of the trees. Nothing moved. "Discord!" He called.
"I was wondering when you'd notice. I know ponies are partial to missing the obvious, but you? Tisk tisk."
"What do you want?"
"Isn't it just typical?" Discord continued, totally ignoring him. "Having to clean up the mess that someone else made. You certainly would never have made such an idiotic mistake."
"Whatever you're doing, stop it."
"Stop what? All I'm doing is saying what you're thinking."
"I'd never think something as ridiculous as that."
"Whatever you say Time Lord, but I think you and I both know the truth. Toodleoo Doctor!" Discord grinned and vanished with a pop.
"Discord! That isn't true and you know it! Discord!"
"Um, Doctor? Are you OK?" The stallion turned around to see the wall-eyed mare and the purple unicorn looking at him worriedly.
"Er, yes. Perfectly fine."
"If you're sure..." Derpy's voice trailed off and it was clear that she didn't believe him at all. The Doctor felt an odd sensation in the pit of his stomach as Twilight's purple gaze turned ever so deliberately from him to the pedestal that Discord once stood upon.
"So you didn't get there in time to stop me from disturbing the time stream, and the resulting temporal waves set Discord free."
"Correct."
"What exactly does that tell us about his capabilities? Did the strain weaken him or was it effortless?"
"I'd need to know more about Discord to be sure. Do you have any records about him?"
"There might be some in the royal archives. However, they will most likely be difficult to find. I lived here for most of my life and I don't recall seeing anything about him."
"It's a risk we'll have to take. Lead the way miss Sparkle."
"Of course, Doctor."
Twilight, unfortunately, was right. No matter how hard the threesome searched they couldn't find anything on the mythical monster, and conditions were getting worse by the day. The physical realm was completely controlled by Discord now. The ground was a pink and purple checkerboard and the sky a swirling cauldron of cotton candy clouds and wind that would sing duets with the birds who had a newly discovered love for opera. The Doctor slammed his book shut and huffed angrily. Twilight and Derpy looked over to see what was wrong.
"That's it! We've been grasping at straws for a week. Or at least what passes as a week in this place. My head hurts from those bloody birds singing and the sun is constantly going up and down. How does that even happen? This stupid planet is still turning at the same rate but the sun and moon are playing peek-a-boo! It isn't possible!"
"This is Discord, Doctor," Derpy told him. "He's a god, and a powerful one. His specialty is the impossible."
"That's another thing. In my experience there's no such thing as a god. Everything that has claimed to be one was lying. There has to be some other explanation!"
"But there isn't," Twilight told the aggravated stallion gently. "Doing all of these insanely powerful spells and not tiring? It just isn't possible if he isn't-"
"A god, I know." The Doctor stood and started pacing.
Derpy flew over to him, narrowly avoiding running into several tables and a bookshelf. "What he is doesn't matter. We know how powerful he is now and we know what can stop him. Why don't you let Twilight and me try and figure out the riddle while you go get some rest? You're looking a little... grey."
"Nonsense." The Doctor yawned. "Time Lords don't need nearly as much sleep as-" he yawned again. "As ponies," he finished.
"Don't argue with me, Doctor. You've been working hard and you haven't fully recovered from your regeneration yet. Go get some sleep and Twilight and I will take it from here, OK?"
Twilight watched with amazement as the hourglass stallion opened his mouth, closed it again, and stomped off, presumably to find a place to take a nap. "Wow Derpy, that was amazing. How did you-?"
"I call it my 'mother voice'. I use it on Dinky all the time. The Doctor has his heart in the right place, but he can act like a foal at times."
Twilight stared at the mare with a new found respect. The pegasus was full of surprises. "I see."
Derpy nodded and let the smile fade from her face. "Twilight, what are we going to do? Every spare moment I'm thinking about that riddle but I haven't made any progress."
"Neither have I," Twilight admitted. "I did find something else though."
"What?" Derpy perked up immediately.
"It's probably nothing."
"At this point every last detail is imperative."
"I know, it's just-" Twilight paused to try to figure out how to put her thoughts to words. "There are little things everywhere, now that I look. Mentions of a mysterious physician and a vanishing blue box."
Derpy nodded absently. "Yes, that would be us. The TARDIS is a time machine after all. I wouldn't worry too much about it if I were you."
"I see." The purple unicorn did her best to swallow her unease but it didn't quite work. She decided not to tell Derpy the other things she had seen in the history books. The bad things. The very bad things. There was no denying that the grey pegasus had seen many things during her adventures with the Doctor. She had most likely seen the rise and fall of civilizations, done her Hearth’s Warming shopping in the next star system, but nothing like this. No, she wouldn't tell the grey pegasus. That gave her a thought. Grey. Suddenly the simple, dull color seemed very, very important.