Hollow Shades was a small town sequestered deep within the unnamed forest at the foot of the Foal Mountains. Most of its population were nocturnal and reclusive, and most outsiders knew the ponies of Hollow Shades only through their presence in Princess Luna's personal guard. The ponies of Hollow Shades had an affinity for darkness, and were able to move in almost-total silence.
Rarity and Applejack were perfectly aware of all of these facts as they traversed the thick woodlands, looking for either the town itself or the rail line that connected it to the rest of Equestria. The forest had no roads or even hoofpaths, only the trains traveling between Hollow Shades and Canterlot connected the town to the world outside. The pair had struck southeast upon entering the forest, knowing that they would reach one or the other of their goals by sticking to that direction. The going was slow, however, due to the densely-packed trees. Despite the assistance of her telekinetic magic, Rarity's hulking warjack and the supply wagon it pulled hindered them even more, forcing them to look for unusually wide gaps between trees. The unicorn refused to abandon her warjack, however, and Applejack wasn't about to leave her friend behind, so both ponies tolerated their slow progress without complaint.
"Hi!" Pinkie Pie said, suddenly emerging from the shadows. Rarity and Applejack both started, and Glam released an angry blast of steam.
"No no! She's a friend!" Rarity told Glam urgently as the warjack began to advance towards Pinkie with menace in its optics.
"Pinkie!" Applejack said with a hoof to her heart, "ya darn near scared the mane offa me."
"I'll say I did," Pinkie replied exuberantly, "you should see the look on your face!"
"Not that I'm not happy to see you, dear," Rarity said, "but why are you wandering around in the forest?"
"I dunno," Pinkie explained unhelpfully, "I just had a feeling I should be out here. Are you three looking for Hollow Shades?"
"Why, yes, we are," Rarity answered.
"Cool! The train tracks are right over there," Pinkie said, pointing vaguely into the dense forest, "we can follow them right into town!"
"So, Pinkie, where're them trolls you were runnin' around with?" Applejack asked, following the pink mare.
"Well, I hung around with Borka and his friends for a while, but in the end I had to leave them," Pinkie answered, "they were headed back up north, and I had a feeling I needed to stick close to Equestria. Besides, Borka was a lot of fun, and on the surface he seemed like a happy guy," Pinkie stopped and looked Applejack in the eyes, "but there's a darkness in him, Applejack. Right in his heart, and I don't think it's safe to be near him."
"That bad, huh?" Was all Applejack could think to say.
"Yup! So, I went to Hollow Shades!" Pinkie suddenly returned to her usual, cheerful demeanor, "then I thought I should wander around in the woods, and I found you and Rarity and your shiny warjack! But I guess you already knew those parts."
"As a matter of fact, we were able to hypothesize those occurrences, yes." Rarity's sarcasm was completely without impediment as it sailed over Pinkie's head, but Applejack had to suppress a chuckle as she caught it. "Tell me," Rarity continued, "have you been to Ponyville or Canterlot yet?"
"Nope!" Pinkie answered, "I just got to Hollow Shades yesterday, and Princess Luna's there!"
"She is?" Applejack asked, surprised.
"Yes indeedie! Fluttershy made friends with some robey humans called the Circling O'r Above-Us or something. They're doing some kind of magic thing in the woods that had some important point to it but I was kinda spacing out when Luna said what it was." Rarity rolled her eyes as Pinkie continued, "Twilight and Dashie are in Ponyville, so now everypony's back in Equestria! And, I think the Princesses kinda want us to stay in Equestria now, so something important must be happening! Isn't that great?!"
"Yes, I suppose it is," Rarity said, "it would have been nice to get some more use out of that diamond mine, but if we're supposed to stay in Equestria, wouldn't that mean we might be returning to our proper world soon?"
"Say! You might be right!" Pinkie declared. "Ooh! Here's the train tracks! Come on, ponies, follow me!"
The first thing Twilight Sparkle was aware of was pain. A dull ache that seemed to permeate her entire body. On top of that, she was still sore where the straps of her Cryxian armor had rubbed her coat off and her skin raw. She decided that the only thing to do was open her eyes and see if she looked as bad as she felt.
Twilight discovered that opening her eyes was a challenge in and of itself, much less getting them into focus. She was rewarded for her effort with a slightly-blurry view of an eggshell-white ceiling, which was quickly blocked by a familiar and welcome, if also quite blurry, face.
"Princess Celestia?" Twilight murmured.
"You're finally awake," Celestia said, clearly relieved. "Thank goodness."
"I'm not sure what happened," Twilight admitted, "where am I?"
"Ponyville Hospital. Allister Caine brought you back to us," Celestia replied.
"Rainbow Dash said we could trust him."
"She would appear to be correct, Caine proved to be both friendly and helpful. He even managed to secure some assistance in one of our little projects. But I'll explain later. For now, just keep resting. Shining Armor's in town, I'll send somepony to let him know you're awake."
Aurora, the Numen of Aerogenesis, felt entirely out of her element in Ponyville. Word had reached the highest echelons of the Convergence of Cyriss that the ponies were seeking mechanika-related assistance from the Machine Goddess's worshipers. As one of the finest Cyrissite engineers still in human flesh, Aurora was an ideal choice to explore whether agreeing to Equestria's request would meet with Cyriss's approval. So, with a directive of subordinate Optifex engineer-priests, Aurora had arrived in Ponyville.
The need for secrecy within the Convergence meant that Aurora's warcaster armor, along with the armor of the three Optifex priests, had to be hidden within a large, steel case, with an elaborate mechanika lock, which could only be opened with Cyrissite magic. Aurora hadn't even been allowed to bring any of the vectors that the Convergence utilized in place of steamjacks, much less any of their clockwork soldiers.
The ponies, too, were secretive about the nature of Project Red River, forbidding Aurora and her subordinates from speaking of it outside of the office in which they worked. Captain Shining Armor had given them a handful of blueprints and diagrams, and explained that his engineers believed themselves unable to create a movement system that could produce enough steam pressure to make the warjack carry its own weight.
Cyrissites placed more faith in precision clockwork than steam power, but Aurora wasn't about to reveal the means by which the followers of the Machine Goddess induced mechanikal movement. For this reason, Aurora and the Optifex priests focused on the steam-conduction systems, finding ways to increase pressure and improve efficiency. The four Cyrissites trusted the Maiden of Gears to guide their design revisions, and the ingenious alterations they introduced to the blueprints were seen by the worshipers as proof of her approval and blessing.
Shining Armor found the Cyrissites mysterious and inscrutable. For three days they had been in the office that Engines Equestria had provided them, not once leaving for any reason. The night guard reported that they didn't even seem to sleep -at any hour of day or night, the room's lanterns burned, the door remained locked, and the sounds of movement and conversation could be heard by anypony with sharp enough ears. When they finally emerged, they made their way immediately to Shining Armor's secondary office at Engines Equestria. Shining Armor often wondered how many offices the Royal Guard planned on assigning to him, but this one was particularly useful. It was situated within the large, windowless building constructed and used by Project Red River, so he and his lieutenants could discuss the Project freely while they were in it, which was precisely what they were doing with Aurora and her three followers walked in.
"We have finished revising the designs," Aurora said without preamble. She spread out a large blueprint on Shining Armor's desk. "We have increased available joint torque by thirty percent in the shoulders, fourty-three percent in the elbows, twenty-eight percent rotationally in the wrists-"
"All right, we get it," Shining Armor interrupted, "thank you for your help, we-"
"Our time in Equestria has come to an end," Aurora cut him off, "we were given three days, and cannot spare any more time. We must return to our people."
"All right, fine, go," Shining said, wondering if all Cyrissites were so abrupt, "and, thank you. You've all been a great help."
"Gratitude is not necessary, we only followed the guidance of Cyriss. The Maiden of Gears has blessed Project Red River, she desires its success for her own reasons. With that, we will take our leave." Aurora and the Optifex directive turned on their heels and left the room. The ponies in the office waited a few minutes before speaking.
"Captain, didn't we need more of an increase than that?" Cherry Cola asked, flexing his right hind leg. The Captain had noticed his tendency to do so almost as soon as his cast had come off.
"Yes, we do," Shining replied with a small sigh, "almost twice as much in the shoulders and elbows, in fact."
"Looks like they pulled off a pretty big boost in the legs, though," Firecracker Burst pointed out, looking over Shining's shoulder.
"What's with all these weird gaps?" Airheart asked, "I'm not exactly an expert, but it looks like there's supposed to be stuff all over the inside that's just... not drawn in?"
"Maybe they weren't really done, and just hit their deadline," Firecracker Burst suggested.
"Let me see," Cherry Cola said, looking at the blueprints from the other side of the desk. Even seeing the design upside-down, he could see the open spaces clearly. Large gaps had been left on either side of the moving parts at the elbows, knees, and ankles. The shoulder, wrist and hip joints were clearly arranged to accommodate things that weren't drawn in. Cola blinked, ideas and memories emerging from the back of his mind, shuffling into place as they always seemed to do. "What about that Iosan stuff Neon Lights and his ponies are messing with?" Cola asked.
"They have been making steady progress," Blue October answered, "how is that relevant?"
"It's relevant because those shoulders look like they're built around a ball joint," Cola pointed out, "the wrists and hips, too. Didn't those Iosan warjacks have ball joints?"
"Cola, I think you're right!" Shining Armor said excitedly.
"And look, the gaps in the other joints look like you could fit something like those weird vane-joints in them, too!" Cola realized.
"there's even a place under the cortex where we might be able to fit one of those arcane reservoirs Neon's report mentioned!" Shining realized, "Cherry Cola, you're a genius! Let me dig out Neon's latest report, we may have this warjack fighting yet!"
The group was interrupted by the sound of knocking. Everypony looked towards the door as it swung open, revealing a Royal Guard in the armor of Princess Celestia's bodyguard cadre.
"Captain Shining Armor," the Guard said with a salute, "Princess Celestia requests your presence at Ponyville Hospital. Twilight Sparkle has awoken."
"Excellent!" Shining lept to his feet, "Cola, get Neon Lights in here to look at these blueprints! I'm going to see my sister!" With that, the Captain dashed out of the room.