“Princess Luna, what is down underneath this castle?” asked the Doctor quickly. He was in action mode now, and he began to talk very fast, pointing with a blue hoof.
“Years ago- centuries- it used to be a mine for precious stones. The walls are made of crystal, but they’ve been sealed off ever since the changeling invasion, nearly a millennia ago.”
“If it’s a mine, there has to be a secondary shaft somewhere, and I bet you it was at the base of the mountain, which would put the entrance smack in the middle of New Canterlot,” he said.
“If the robots are protecting whatever’s down there, maybe that means the ponies making them have something secret they don’t want anypony to see,” suggested Derpy.
“Aha!” the Doctor exclaimed, “They knew teleportation was sealed off, so they built a shop right over the mine entrance! Princess, how many robot dealers are there in New Canterlot?”
“Three,” she answered, looking up as she tried to recall the names of the companies.
“There’s Cogstad Corp, Robotech, and Ironclad Industries.”
“We’re going to need to split up,” the Doctor said, taking to the stairs, “Your highness, do you want to help?”
“Gladly,” replied Luna.
“Fantastic!”
****
The three ponies walked down the main strip as night began to fall. As the sky darkened above, the bright lights and transparent advertisements of buildings and skyline glowed even brighter to compensate. The nightlife started to emerge as ponies who slept most of the day awoke and began going about their business. Princess Luna wore a cloak over herself to prevent attention being drawn to her.
“Here’s the plan,” the Doctor said, “We’re going to have to split up into two groups, and that means I’m on my own. Princess, can you do that message-teleport thing that your older sister does?”
“Are you asking me if I can send messages to you via magic? Yes.”
“Fantastic- now I’m going to check out Cogstad first, you two can choose between Robotech and Ironclad. First group that finds anything useful to point us in the right direction gets the others.”
“What are we looking for, Doctor?” asked Derpy, stretching her front legs out and arching her back.
“They’re not going to want you to get anywhere near the entrance, so insist of seeing every square meter of the building. If they get testy, press a bit harder until the robot does what it did earlier. Princess?”
“Yes?”
“Don’t let anything bad happen to Derpy. Good luck, you two.”
****
As Derpy and Luna walked down the road via sidewalk, Derpy felt completely alone in an alien world. The sidewalks glowed bright colors here, and every hoofstep she took made it shift around and ripple with light like a puddle of water. The robots all around, no matter how much dressed up or prettified they may have been by their owners now posed a potential threat, and that was unnerving.
“So, Princess, erm...”
“Luna,” the cloaked alicorn said, “My name is Luna. You don’t remember me, do you?”
“When I come from, there’s only two princesses,” Derpy explained, “Celestia and the much younger Cadance.”
“Since you travel with the Doctor, I think it’s alright to spoil some things. In your time- the early 21st century?”
“Late 20th. Like, the tail end of it,” corrected Derpy.
“Well, I was imprisoned in the moon up there at that point. I had a thousand-year sentence, and the time was up in 2010. I broke free as a terrible monster bent on revenge, but then six friends tamed that wild beast using very powerful magic. I was.... rehabilitated in a way. I joined my sister’s side, and it took a year or two to get back up to date with current culture.”
Derpy paused, passing by a sign near a gravity bus station that showed a three-dimensional map of downtown New Canterlot. She stuck a hoof to the point showing where they were, and traced the path they would need to take to get to the Robotics dealer. Just a few more blocks.
“But enough about me,” Luna said, “What about you? What’s life like? You and the Doctor, travelling together all over time and space?”
“This is the first place he’s taken me,” Derpy said, “It was gonna be a quick trip until we got zapped to the Castle, then came all of this robot stuff.”
Luna stopped, motioning for Derpy to look at her. The princess poked her snout out from beneath the cloak, examining Derpy’s face. She peered at her slightly-off gaze, at her scruffy blonde mane, and her youthful features.
“You look like a filly just out of her teens. How old are you?”
“19, turning 20 in about a week,” Derpy replied. Luna released her, tapping her hoof to her chin.
“So you just met the Doctor?” she asked, continuing to walk down the busy sidewalk.
“Yes,” replied Derpy, “He saved me from the Synax, and I saved him in return. I don’t know him that well, he’s almost a bit of a stranger to me still, but he’s told me enough that I know that I can trust him.”
“Like what?”
Derpy paused.
“I’m not sure I’m supposed to tell.”
“Derpy,” Luna pressed, “Did he tell you that he was the last of his kind? That he wasn’t even a pony at all?”
“...yes, how did you know that?”
Luna laughed.
“You were the first pony he ever revealed that to, about him being the last Time Lord. I was the second. Don’t forget, you two meet up with the past me later, at some point.”
Derpy’s eyes crossed, and her face contorted in an extremely confused expression.
“Ugh, time travel.”
****
The Doctor strolled casually into the storefront of Cogstad robotics. Cogstad specialized in mostly industrial robots, and the storefront reflected that purpose. The walls were rather gray plain, and painted a criss-cross of yellow and black in the corners as a sort of factory motif. The lights in the ceiling above were square, and the robots on display angular and bulky. These were the heavy lifters, the true workhorse of 30th century Equestria.
A clerk of some kind came forward, looking with bewilderment at the Doctor.
“The sign says that we’re closed, and I locked the door! How did you get in?” the gray-maned stallion asked.
“It wasn’t locked,” the Doctor lied, pocketing his sonic screwdriver and withdrawing a leather wallet with a slip of paper on the interior, holding it up like a form of identification.The clerk looked at the slip of paper, lifting up his glasses carefully.
“Oh, dreadfully sorry Inspector,” he apologized profusely, “I must have misread the schedule, I thought you weren’t due until next week!”
“Maybe you mismarked it in the first place,” the Doctor said, “Now if you’ll excuse me, I need to do a structural integrity test. I’m gonna walk the length of the building, the entire building. Any broom closet, bathrooms, storage shed, they all need to be checked.”
“What for?” asked the stallion as the Doctor wheeled about toward the far wall of the complex. The Doctor’s head craned back to glance at him.
“Testing the structural integrity, of course! Now give me space.”
****
“Welcome to Robotech industries,” welcomed a smooth-voiced clerk pony with an ivory coat and a silky mane. The inside of the robot retailer had that typical futuristic look to it, right down to the streamlined curves of the furniture and lights and the ever-present chrome finish. Derpy looked at the wall, seeing her reflection and giving herself a goofy grin. Virtually everything in this place was polished and reflective.
“Hello,” Luna introduced herself, taking her cloak’s hood off and revealing herself. The clerk seemed quite surprised to be visited by a royal princess, as she dropped herself immediately into a deep bow.
“Oh, your highness,” she said, “We are humbled by your prescense. Please, if there is anything we can do for you, let me know at once.”
“Surprise Royal Inspection, I’m afraid,” said Luna, “My assistant here will accompany me around the facility.”
“I didn’t know we were going to have a Royal Inspection!” gasped another staff member.
“Hence the ‘surprise’,” remarked Luna with the slightest of smirks, “Come along now, Derpy.”
****
The Doctor stood inside the outer edge of the garbage chute, leaning with his hind hooves and stretching his glowing sonic screwdriver out into the structure ahead of him. The air inside the shaft smelled odd, though not foul. When the sonic returned no useful information, he went back onto all fours and closed the hatch of the garbage chute, pocketing his screwdriver.
“Well, that’s every single meter of wall I could find, and not a single structural weakness,” the Doctor congratulated the clerk, “Though I did notice an odd scent in the garbage chute. Have you been dumping Rubidium?”
“Yes,” the clerk answered honestly, “We had a case of spare holo-emitters. You know, spare parts for robot repairs. The occasional customer wants them fixed. So, one of my colleagues tested the emitters and found that the entire boxful was susceptible to overload. Since rubidium is used in the emitters, that’s just the smell of a few of them breaking open inside the garbage chute.”
“Improper disposal of alkali metals,” the Doctor said with a fake sigh, “I’m sorry. You were doing so well, too. Still though, that’s a near-perfect score. Mind if I ask, though- where’d you get the bad holo-emitters?”
“Well,” the stallion responded, squinting and adjusting his spectacles, “I think they were industrial supplies from Ironclad Industries.”
****
“What’d you find?” asked the Doctor. He, Luna and Derpy all sat on a park bench in the center of New Canterlot, on the corner of two streets. Traffic and turbo-carriages zoomed by noisily, though they were still able to hear each other.
“Robotech shows nothing,” Luna said simply, “No bad reactions from the robots, or anything odd when we took a complete tour.”
“We literally looked in every single part of that building,” Derpy said distastefully, “What about you, Doctor?”
“Well, I think I found a source on those bad holo-emitters. Turns out Cogstad got sold some holo-emitters from Ironclad Industries that overloaded on them. Sound familiar?”
“So Ironclad has the technology to make the robots be able to shoot off like that one in the castle?”
“It’s a place to start,” replied the Doctor.