The Emperor and Empress of the Crystal Empire, Shining Armor and Cadance, accompanied by a hooded Astral and a platoon of the Crystal Praetorian Guard, stood together on the Crystal Empire airfield as the Slipstream slowly descended. The mooring lines automagically secured themselves to the ground and a gangplank extended before touching ground, revealing Midnight and Twilight standing ready to disembark the airship.

The sapphire alicorn stallion and the lavender alicorn mare were disheartened to see smoke still rising from here and there around the Empire. But they quickly presented themselves with strength and elation as they came down, followed by Spike, their apprentices Starlight and Sunburst, along with Captain Firestorm, his Lieutenant Nightling, along with four Harmony Guards, two of the Dawn Division, the other two of the Dusk.

"Halt." Midnight and Twilight were a little taken aback as one of the Praetorian Guards stepped forward and lit up his horn to cast some kind of spell.

The unicorns could sense it was some kind of abjuration, most likely to detect any magical form of disguise. Once it was over, the guard gave a respectful nod, "Apologies, Your Majesties.

"We had to make sure you weren't in disguise."

Midnight and Twilight shared a troubled look before looking over to Shining Armor and Cadance. Cadance stepped forward cautiously, "Sunshine, Sunshine, ladybugs awake..."

Twilight smiled and stepped forward to do the rest, "Clap your hooves and give a little shake."

Cadance smiled in relief while their husbands approached each other... and then saluted as they both said in perfect synch, "To Equestria, I pledge my life, along to everypony. To safeguard all from fear and strife, alongside my best brony!"

They both chuckled in relief before hoofbumping and Shining Armor said, "I apologize, everypony, for the iffy welcome wagon..."

"There's no need to apologize, BBBFF," Twilight assured as she came over to give her big brother a hug, "In light of what's happened..."

"Astral," Midnight looked at the hooded dragon, "What’s the situation?"

"Sir!" Astral stood upright while saluting Midnight before reporting, "Earlier this morning, I was following my usual routine, about to go out for breakfast, when I sensed something was not right...

"I spotted a changeling in an alleyway and was about to pursue him. But he'd left something behind, a strange device that... beeped, and I realized what it meant, just barely protecting myself with a Mana Shield, before it suddenly exploded. More explosions went off around the Empire and in the panic and madness, I... I am afraid I lost sight of the changeling."

Astral hung his head in shame, though Midnight kindly said, "It's alright, Astral. Please, continue."

Sighing, Astral went on, "I was disoriented yet adrenaline spurred me on so that I didn't notice my injuries. I quickly noticed that many citizens around the blast areas had-had... urgh!"

Astral grimaced as he clutched his shoulder, Cadance going over to let him lean on her as she said, "Don't push yourself, Astral."

Shining Armor stepped forward, "No fatalities, no serious injuries, but the ponies who were near the sites of the explosions...it's as though they had been reverted to the dismal state they were in back when the Empire first returned. Almost as though...as though all their positive energy or something had been sucked out of them!"

"Oh my goodness!" Twilight remembered how the Crystal Ponies were back when the Empire first returned. She and her friends had spoken with many of them in the hopes of learning of some method to protect the Empire or of the monstrous tyrant Sombra once was, only for them to refuse to talk about it because they couldn't nor desired to remember any of it.

"And that's not even the worst of it..." Astral spoke up while giving Cadance an assuring gesture that he was alright, and she let him stand on his own.

"Whattya mean?" asked Spike, concerned.

Cadance, Shining Armor, and Astral shared a troubled look before Shining Armor answered, "It's the Crystal Heart. Something is wrong with it, it's starting to turn green! Almost as though... it’s been infected with something!"

"Infected?" Twilight was aghast. "I know the Crystal Heart is alive with magic, but... If it's alright with you all, could I have a chance to examine the Heart? See what we're dealing with?"

"I was hoping you'd offer, Twily," Shining Armor nodded, "we have magical experts but none of them are as good or knowledgeable as you."

"Alright then, Starlight? Please come with me," Twilight ventured forward, Starlight following.

Spike almost followed but Cadance said, "Spike, if you wouldn't mind, would you go see Thorax and Elytra, help them look after the baby? I would really appreciate it."

"Oh, sure!" Spike didn't mind at all, plus he'd get to catch up with his buddy Thorax, and Cadance instructed a guard to escort Spike to the secure room where Thorax, Elytra and Cora were all staying in for the duration of this crisis.

"Sunburst, go with Twilight and Starlight," Midnight ordered.

"But... shouldn't I stay with you, Midnight?" Sunburst was a little surprised.

"They'll need all the best magical experts they can to figure out what's going on with the Crystal Heart," Midnight explained, "and you're my wife's peer in magical expertise."

"Makes sense," Sunburst nodded before hurrying to catch up with Twilight and Starlight.

Midnight then looked to his brother & sister-in-law, "What about the victims you spoke of? Where are they?"

"We moved them to the hospital," Shining Armor answered, "but only after we did a thorough sweep of the whole building to make sure nothing dangerous was set up there, as well as counted for every single member of medical staff.

"I'm afraid whatever's going on, it's not over."

"It all but certainly isn't," agreed Firestorm as he stepped up to stand beside Midnight. "This is clearly an act of terrorism, and horrific as what's already transpired is, I'm afraid there is most certainly a bigger endgame the culprits have in mind."

"Firestorm, I would like you and Nightling to coordinate with Shining Armor and oversee the Praetorian Guard," requested Midnight before addressing Shining Armor, "If that's alright with you."

"Sounds good to me, and it'd be an honor," Shining Armor agreed while giving a respectful nod to Firestorm who saluted in response.

"Cadance, you should check in on the afflicted ponies," suggested Midnight, "I expect Twilight will want to see them once she's done checking out the Crystal Heart, see how the two are connected."

"Agreed," Cadance nodded before looking at Astral.

Before the hooded drake could say anything to her, Midnight spoke up, "And Astral? I would like for you to show me where exactly you saw the changeling, as well as any reports regarding the explosions."

"Yessir," Astral gave a respectful bow to his superior before giving Cadance an assuring pat on her withers and leading Midnight towards the damaged district where the whole thing had occurred.

The air was thick with fear and worry. Every citizen they passed by was afraid and on the lookout for potential danger, even with the Guardsponies out making patrols. Before long, they arrived at the alleyway where Astral had seen the changeling set up the explosion, and Midnight was glad it had been cordoned off with crime tape.

Stepping into the alley, the hooded alicorn and hooded drake took a closer look at the blast site.

"Whatever this explosion was," Midnight sniffed carefully, "it wasn't incendiary though it was certainly an instant release of energy, given the damage. The fires were caused by damage to electrical systems in the buildings directly affected by the blasts."

He pointed out how the area in the alleyway looked damaged and de-structured, shards and debris of crystal from the adjacent buildings littering the ground.

"I barely got a glimpse of the device before it exploded," sighed Astral, "It was about to explode and I had to protect myself with a Mana Shield or-"

"Hey." Astral stopped and saw Midnight giving him an understanding look, "You did what you had to do and you're still here to do your duty. Whoever did this is the one responsible for the damage, and we're gonna get him."

Nodding, Astral looked around the site again, wondering, "The explosions were loud and flashy but apart from minor injuries, as well as their strange conditions... nopony died and no one was seriously hurt.

"Was that a fluke or intentional?"

"Depends on what their intention actually was," Midnight considered the question before asking, "Was this the first explosion? Your report said there were multiple blasts. Did they go off in a sequence or were they all basically simultaneous?”

"Hard to say," Astral sighed as he ran the experience through his head again, a pit in his stomach conflicting with the relief that he was still alive.
"I was so close to this explosion that although I protected myself I still got rattled. I heard the others, but I can't be sure if they all went off at the same time or even afterwards.

"The investigation is still trying to determine the time-frame of the explosions and what kind they were before they went off."

"But you saw a changeling set up this one," Midnight pointed out, "and shortly after you almost chased him, the device was remotely detonated or, as you noticed the rapid beeping, it was on a timer or was perhaps activated via pressure sensing or proximity.

"I'm all but certain that this was the first explosion or at least it went off along with the rest almost simultaneously."

"So... then perhaps this one was the last explosive device set up but when I chased the changeling, he had to set them off to salvage whatever he's up to," added Astral.

"Either you caught him setting up the last device or you interrupted him," Midnight nodded. "If it's the latter, he's probably not happy right now that his plans might have been rushed prematurely."

"If that's the case..." Astral gulped nervously, "his next attack might have real casualties."

"Which means we haven't a moment to lose," agreed Midnight. "Let's go see them at the Crystal Heart."

In the courtyard beneath the crystal castle, right where the Crystal Heart was kept on its pedestal, Twilight, Starlight and Sunburst examined the relic with careful concern. They'd tried spells to dispel any malevolent magicks, ward off any outside influence, but they weren't exactly sure what was wrong so their efforts amounted to putting a band-aid on a broken leg.

Sighing, Twilight asked, "And that was... the eighth spell?"

"Ninth, actually," Sunburst corrected while pushing his glasses back in place. "I thought for sure the Albion Abjuration would work!"

"What exactly is wrong with it?" Starlight stared at the Crystal Heart, floating like a dreary balloon whose helium was running out, its lower side giving off a poisonous green glow.

"Well that's just it," Sunburst concluded, "Until we determine the cause, we won't be able to determine the method that will fix this."

"We need more information, and I really hope-" Twilight was saying when they heard approaching steps and turned to see Midnight and Astral coming their way. "Midnight!"

She went over to hug her husband and he warmly obliged before asking, "Any luck?"

"None," Twilight sadly reported, "Whatever's wrong with the Crystal Heart, we can't figure it out or how to help it."

Astral looked despondently on the literal heart of his protectorate, which didn't go unnoticed by Midnight.
"This isn't your fault, Astral. What matters is that you do everything within your power to make it right again."

"...yessir," Astral took a deep breath, "I need to be strong. Everypony else's spirits are down, I can't let them see me that way."

Astral's words seemed to click in Twilight's mind as thoughts and tidbits of information started to run through her mind's eye. She looked back at the Heart, and considered the Crystal Empire, the Crystal Ponies, the fact that the victims had been somehow reverted to their depressed and dull conditions like they were when she first met the Crystal Ponies...

"...that's it!" Twilight whispered in revelation!

All eyes turned to Twilight before Midnight asked, "What's it, Twily?"

Twilight approached the Crystal Heart, scrutinizing its facets and the sickly green glow in its lower side before she turned around to face them all and said, "The Crystal Heart is powered by the love and hope and all other positive emotions of the Crystal Ponies throughout the Crystal Empire!

"The victims of these strange explosions, it's as though they've been drained of their positive emotions! Ergo..."

Twilight invited them to figure out where she was going with this and Sunburst was the first to get it, "Of course! Because some of the citizens have lost their positive emotions, that's having a negative effect on the Crystal Heart as well!

"Perhaps whatever has afflicted the victims is also having a negative effect on the Heart as well through them!"

"That makes perfect sense...!" Midnight realized, seeing the dots connect, "Without positive emotions, the Heart will weaken, but whatever is happening to cause this is also causing this strange side-effect on the Heart as well."

"Which means we have to find a way to restore positive emotion to the afflicted citizens," proposed Starlight.

"How would we do that?" Astral brought up, "We can't exactly have a Crystal Faire, with an enemy on the loose. Large gatherings of citizens would put them at risk of further attacks."

"That is true," Midnight considered, "events that draw in crowds are favorite targets of terrorist attacks. I'm afraid we're gonna have to track down this enemy and bring them in before we try something big to lift the citizens' spirits.

"Once the threat is taken care of, it should be safe."

"But what about the Heart?" Starlight gestured to the relic. "There's a chance that its condition could get worse unless we can either refresh it with positive emotion or at the very least purge it of whatever is infecting it!"

"Then perhaps..." All eyes turned to Midnight as he gave Starlight and Sunburst a teasing grin, "the two of you should stay here. Maybe your blossoming romance can be of help to the Heart while Twilight, Astral and I go speak with Cadance."

Starlight and Sunburst blushed heavily and started sputtering causing everyone else to start laughing.

Giggling, Twilight nodded, "The two of you should continue to study the Heart, find out more if you can. As Midnight said, we'll check on the afflicted and see what we can determine from their conditions."

"Comet," Midnight spoke to one of his guards, "Remain here and assist Sunburst and Starlight if necessary. If something comes up they can send you to inform us of any developments."

"Yessir," Comet Tail nodded.

The two alicorns and drake made it to the hospital where they found Cadance in the waiting room, pacing back and forth in worry.

"Cadance..." She looked up to see her sister & brother-in-law arrive, along with Astral, who asked, "How are the patients? Any improvement?"

"I'm afraid not," fretted Cadance, "I can't say if they're getting worse but their condition has... changed."

"What do you mean?" asked Twilight.

"It might be easier if you see for yourself," Cadance led them to the wing where the patients afflicted by the explosions were being treated.

They laid in rows of beds, several doctors and nurses attending mares, stallions, fillies and colts. Whatever bombs the changelings had created, they apparently didn't discriminate and could affect anypony too close to the explosions' effects.

The patients were all dull and depressed, some moaning, others even looked like they had tummyaches or something. Worse were the ones crying or staring off into nothing.

Grimacing, Midnight gingerly said, "Well... they don't seem any worse than the reports indicated."
"Look at their eyes," Cadance pointed out as she led them to a filly's bedside, the poor thing whimpering as she stared at nothing at all... with her pupils giving off a faint but discernible green glow!

"By the Drakon...!" Astral uttered in deep concern.

"Why are their eyes glowing like that...?!" Twilight was aghast.

"I don't know," Midnight gave the filly a closer look, but the filly gave no indication she was aware of Midnight's presence, "but it looks like this glow is the same green as the one on the Crystal Heart!”

"It seems your theory is correct, Princess Twilight," Astral sighed, "the victims' conditions is related to the condition of the Heart."

"What does that mean?" Cadance looked to her sister-in-law.

Twilight quickly explained the theory she arrived at earlier and Cadance worried, "That makes sense... the Crystal Ponies are the source of the Crystal Heart's power! Because some of them have been drained of their positive emotions..."

"...the Heart is likewise suffering some kind of malediction," Twilight nodded.
"We need to learn more and figure out how to restore these ponies to their positive minds."

Just then Astral felt himself about to deliver a message. He opened his maw and burped out a small gout of fire in the air so as not to accidentally hurt anyone.

"Who sent the scroll?" Twilight asked.

Astral looked at the seal and said, "It's from Shining Armor. It's addressed Midnight," he burped and another scroll came out, "still from Shining but for Midnight."

"Lemme see those..." Midnight undid the first message's seal and read it over, "Shining Armor wants to see me and Astral. He says... Sunburst found something about the bombs!"

"What did he say Midnight?" Cadence asked.

Looking at the second scroll, Midnight found what he was looking for.
"He says that Sunburst spoke with Thorax, and in addition to what they found out about the bombs themselves Sunburst has a theory as to what the changelings are doing.”

"You should go speak with them, Midnight," Twilight said before kissing her husband on the cheek. "I'll stay here with Cadance and help with the patients."

"Be safe and keep your guards with you," Midnight muzzle-nuzzled his mare before saying to Astral, "Let's go!"

"Right behind ya!" Astral saluted as he followed Midnight out of the hospital.

Midnight and Astral arrived at Sunburst’s old residence back when he still lived in the Crystal Empire. The two-stable crystal house, colored orange and green and the roof shaped uncannily like a wizard’s hat, now served as a magical laboratory. Shining Armor and Cadance had kept it for Sunburst and Midnight had arranged for the domicile to be outfitted with equipment, books, and other things for magical research and development.

Inside, they found Shining Armor and Starlight watching Sunburst pacing back and forth, a look of subdued excitement on his face, showing he was eager to share his thoughts.

"Sunburst, would you calm down?" Starlight sighed in slight humor, "You're wearing a groove into the floor."

Sunburst paused to look at the floor, "So I am."

He was stepping out of the groove when he noticed Midnight and Astral were present, as well as amused as well.
"Oh! Midnight, sorry, I- I didn't hear you come in."

"No worries, Sunburst," Midnight assured his student, "We came as soon as Shining Armor sent us the message. What's this theory you've come up with?"

"Right! Straight to the point," Sunburst led everyone over to a worktable, where bits and pieces of something lay, a nearby marker board with scribbles, notes and even a diagram that showed a vague spherical shape.
"So, the investigative team was able to find rather few pieces of the bombs, but from what I've been able to conjecture from what they did find..."

Sunburst pointed to the diagram, "I believe the explosives were generally shaped like this. What do you think, Astral?"

"Well..." Astral gave the diagram on the marker board a close look, "I only had a glimpse of it before I had to shield myself from the explosion. But... yeah, I think this may match the device I saw."

"Well, anyway, the evidence I've gone over from the bomb fragments," Sunburst gestured to said fragments, "leads me to believe that these bombs aren't incendiary."

"I figured that too," Midnight concurred, "When Astral showed me where the bomb he saw went off, I found little-to-no traces of scorch marks or anything getting torched. It's as though the bombs released a sudden burst of sheer force."

"Not force, air!" Sunburst corrected, "These bombs, like you said, weren't incendiary, but rather... they contained super-condensed amounts of air! Now, we all know what happens to a balloon when you poke it with something sharp."

"It pops, makes a bang," Shining Armor interjected.

"Yes, these bombs were basically balloons with an incredible amount of air contained inside of them!" Sunburst went on, "along with other elements, such as some kind of detonation mechanism, something that is most certainly changeling magic-based... and fireworks!"

"Fireworks?" Midnight echoed in confusion.

"Magical fireworks were added to the bombs to make a flashy explosion in addition to the sudden release of so much air, which explains the force of these explosions," Sunburst nodded before levitating something else from the table.
"In addition, there were these! Crude but serviceable electromagnetic pulse devices, which went off along with the bombs, creating EMP effects to short out or damage any nearby electrical or mechanical systems, which also explains why some electrical systems shorted out and even caught fire, creating incendiary effects."

“Okay, the magnitude of the explosion, the fireworks for an incendiary effect, the emps, and whatever this changeling magic that drains positive emotions from nearby victims," Midnight listed it all off before asking, "but Sunburst, what's this theory you mentioned in the message?"

"Right, sorry!" Sunburst put the stuff back on the table before stepping over to the markerboard and turning it around for the blank side.
"I had a word with Thorax about how these bombs are apparently stealing positive emotions... and he said something that intrigues me - Changelings are always hungry for love and other positive emotions, but all this? The explosions, this attack on the Empire... it's counterproductive."

"What does that mean?" asked Astral.

"Well think about it," Sunburst explained, "These bombs are apparently a new way for the changelings to-to... harvest positive emotional energy! So, judging from the number of afflicted ponies by this incident, it does indeed mean they would acquire a large supply of positive emotional energy..."

"But...?" pressed Starlight.

"But... it's a supply," Sunburst pointed out, "Finite, limited, and then afterwards the method is no longer productive."

"Why's that?" asked Astral.

"Because of what it's done to the Empire as a whole!" Sunburst answered with an almost manic gleam in his eye.

He stopped talking, letting his words sink in for a moment before Shining Armor realized, "This attack... it's got the whole Empire alert and afraid!"

"Bingo!" Sunburst drew a simple picture of the Empire on the marker board and then drew the spots where the explosions went off.
"There were... nine explosions altogether, each of them in a place that was guaranteed to have lots of ponies there."

"The bakery where I go for breakfast every morning," Astral pointed some of them out, "the library, the spa, the new cinema...."

"Yes, and that guaranteed that as many ponies as possible would be afflicted by the effects of the bombs," Sunburst elaborated. "But as I said, as much positive emotion as this has given the changelings... it's still counterproductive because this sort of method guarantees that afterwards the populace will be afraid, scared, angry, suspicious. Negative emotions that no changeling would touch unless they were absolutely desperate for any nourishment whatsoever!"

"So then what are you getting at, Sunburst?" Starlight was begging to get impatient.

"...I think this is an experiment!" Sunburst answered almost as though it were an obvious conclusion. "As far as we know, the changelings have never done something like this before. They've attacked, invaded, stolen victims to serve as livestock for them to collect positive emotion from... but this seems like something entirely new!"

"So what you're saying is...these bombs are some kind of prototype," surmised Astral.

"Most likely, because if this had already happened elsewhere in Equestria we would have heard about it," replied Sunburst, "The changelings must be trying to work out a new and more efficient method of harvesting positive emotion and they chose here because the Crystal Empire has more Love and positive emotion than anywhere else in Equestria!

"Odds are, they'll take what they can, learn what worked and what didn't and determine how to improve this method with their next test!"

"Which means their next tests could prove to be even more dangerous than what's already happened..." Midnight furrowed his brows. "Astral, if you hadn't spotted the changeling setting the bomb up we'd have never known they were behind this to begin with!"

"Well done, Astral," Shining Armor gave the drake a teasing salute, making Astral shrug and smirk in a slightly bashful way.
"So... if this is really an experiment, the changelings must have a hideout somewhere nearby where they're holed up. The question is where? We're doing regular sweeps of the city to make sure no one is a changeling in disguise or has been replaced by one, and so far the bugs haven't been detected."

"If the changelings aren't in the city..." Midnight deduced, "they must be on the outskirts near the Thermal Barrier's perimeter or even just outside it. But it would have to be somewhere they can be safe for a period of time, somewhere dark, sheltered and warm.

"We'll need to send teams of scouts with the right sensory spells to detect any changeling presences out there."

"Thorax has been a great help with that, actually," agreed Shining Armor, "he volunteered to let us examine him and his magic so that we could devise the means and methods for detecting changelings.

"We know they work because we tried them out with him and Elytra disguised while playing our own little game of hide n' seek. The little wuvbug had the time of her life."

"Heheh, you're really fond of those two, aren't you?" giggled Starlight, finding Shining Armor's words and the smile on his face from reminiscing cute.

Before Shining Armor could reply, Astral hurked, looking like he was about to barf... when he burped up a stack of papers thick enough to make an encyclopedia blush, along with a scroll with Twilight's mark on it.
"Urp! Whoever did that should send this stuff a little at a time..." Astral thumped his chest while gulping, trying to keep his breakfast down.

Sunburst picked up the stack of papers and saw that it was research, and then looked at the scroll and sensed a charm that indicated the intended recipient. He floated it to his master, saying, "This is for you."

Midnight read the scroll before saying to Shining, "It looks like Twily's figure out why the victims aren't getting better. She wants to meet us in the throne room."

“Let’s get back there,” Shining Armor declared and they hurried out the front door.

As the group left Sunburst's old house, they were unaware of a crystal pony watching them from a distant rooftop... only to be engulfed in purple-red flames to reveal his true form as a changeling with a purple carapace and eyes and a red frill on his head.

Closing his eyes before opening them again to reveal a pair of green pupils looking out through his eyes, he thought, Your Majesty, the plan is in motion and is going according to your design...

Excellent work, Pharynx, echoed the voice of Queen Chrysalis in Pharynx's head. Wait for the opportune moment... and then move onto Phase 2.

Yes, my Queen, Pharynx thought as he felt his queen-mother dull the connection, returning him to lucidity and he disguised himself again before sneaking off.

It'd been a risk to drop his disguise but the Hive Mind was clearer when in one's true form, especially when so far from the Queen. Not to mention, he needed for his Queen to see through his eyes to assure her things were going smoothly.

Pharynx avoided a patrol making rounds and then looked towards the Crystal Castle, thinking, Enjoy what you have while you still can... because you'll never see what's coming next!

He chuckled to himself as he made his way towards his next destination.

Next Chapter: 393. Crystal Quest - Part 3 Estimated time remaining: 11 Hours, 59 Minutes