Lightning flashed across the stormy skies over Ponyville, followed shortly by a crack of thunder loud enough to rattle the windows of the houses down below. Sheets of freezing rain poured from the heavens in a torrential downpour, soaking any soul unfortunate enough to be caught outside that evening.

Rainbow Dash loved the weather. She soared through the skies riding the powerful storm winds, enjoying the sheer thrill of being out in such dangerous weather. Nothing got her adrenaline pumping faster than dodging lightning bolts or feeling the shockwave of a thunderclap squeeze through her body and force the air out of her lungs.

A brilliant stroke of light heralded the next lightning bolt, and Rainbow banked left to avoid it. To her great surprise, it terminated less than ten yards from her right with a blinding flash followed by a deafening thunderclap. When her eyes and ears recovered, she noticed a gray pegasus heavily laden with saddlebags flying slightly above her and to her right, yelling something into the wind.

"What?" Rainbow asked, flying closer so she could hear him.

"I said you shouldn't be flying in this weather," the stallion shouted, with a distinct Canterlot accent. "Cloudsdale civil aviation code chapter 3 title 1 section 102 clearly states that—"

"You have got to be kidding me," Rainbow yelled back. "I'm in charge of the weather here! I know what it says!"

"Then you know better than to be out here! The chances of getting struck by lightning—"

"Please, I've done this a hundred times! I'm too awesome to get hit by lightning."

"You're being ridiculous! Lightning will try to discharge into the nearest object capable of bearing a negative char—"

The explanation was cut short by another lightning bolt which scored a direct hit on the pegasus. Rainbow could have sworn she saw his skeleton light up for a moment before his smoking body plunged straight down towards the ground. She stared in horror for a moment before her instincts kicked in. Rainbow tucked her wings in tightly to reduce the drag on her body as she dived to catch him.

200 meters. 150 meters. 100 meters. 50 meters.

Rainbow Dash wrapped her hooves around his limp body a dozen meters above the Ponyville town square and pulled upwards sharply. His body jerked as she stopped him from hitting the streets, hard enough to bring him back to consciousness. He shook himself out of Rainbow's grasp and landed on the ground, only for his legs to give out from under him.

He lay in the mud unmoving as the smell of burned hair filled the air. "Why am I smoking?"

Rainbow laughed nervously as she scratched the back of her head with a hoof. "Yeah, you, um, might have gotten struck by lightning when you were telling me to stop flying because I might be struck by lightning. Gimme a sec to make sure you don't have a concussion or anything, alright?"

The stallion groaned and rolled his eyes as he endured a prompt checkup. Rainbow looked into his green eyes to make sure they were focused before running her hooves through his frazzled dark blue mane, ruffled wings, and docked tail to check for burns.

"So tell me, doc, how long do I have?" he grumbled as she inspected his horseshoe–clad hooves for injury.

"Oh, I'd say two, three centuries tops," Rainbow replied casually as she tugged his saddlebags back into place, inadvertently revealing his cutie mark: a sphere of electricity.

He shook himself free of her grasp and drew himself upright. "Well, at least I'm in Ponyville now. I don't suppose you could point me towards the library?"

"Don't tell me you came through the storm to check out a book? I know you eggheads love reading, but—"

"I'm here to see Princess Sparkle," he snorted.

"Oh, really?" Rainbow's eyes lit up. "Cool, I'm friends with her! Let me take you, it's right down the street."

Before the stallion could respond, Rainbow trotted off towards the library at a brisk pace, leaving a confused pony in her wake. He shook his head and followed her with weary resignation. It was not long before they stood under the branches of the Golden Oaks Library, with Rainbow Dash enthusiastically knocking at the door. After a brief pounding, it opened to reveal a disgruntled Spike.

"Do you know what time it is?" he grumbled. "I was about to go to bed."

Rainbow gave him a hearty smack on the shoulders. "Nice to see you too, Spike. Is Twilicorn still up?"

The stallion glared at her upon hearing the irreverent nickname, while Spike simply shrugged.

"Is it before midnight? Then Twilight's should still be in the study."

"Thanks, Spike!" Rainbow walked in followed by the pegasus, while Spike yawned and went back to his bed. The two entered Twilight's private study, where she was busy searching through an ancient tome filled with arcane writing. They stood patiently for thirty whole seconds for Twilight to notice their presence, with Rainbow constantly clearing her throat. The stallion seemed content to wait for however long it took, but Rainbow had had enough. She picked up a crumpled sheet of parchment from the wastebasket and threw it at Twilight's horn before her companion could stop her.

Twilight's head shot up immediately and she caught the piece of litter in the air right before it hit the ground. The stallion found himself impressed; the princess had great reflexes, even for an alicorn.

Twilight looked around to see who had thrown it and smiled. "Rainbow Dash!" Twilight pushed the book away and got out of her seat to greet her friend. Rainbow gave an enthusiastic high–hoof, while the pegasus dropped to his knees.

"Your Highness," he said while facing the floor.

"Oh, um… Hi there!" Twilight looked flustered at the royal attention. "Who are you?"

"Lt. Thunderball, SIS," he answered stiffly, keeping his eyes focused steadily on the ground. An awkward atmosphere filled the library as he remained kneeling in front of her.

"Er… You can get up now. No need to stand on ceremony for me."

Thunderball finally rose and stood at attention. "Thank you, Your Highness."

Twilight sighed, while Rainbow Dash giggled. "So, Lieutenant, to what do I owe the honor of this visit?"

"Princess Celestia has asked that I brief you on the status of changeling infiltration in Equestria and that I assist you in apprehending any changelings present in Ponyville."

Rainbow took a step back from the conversation. “Sounds like that'll take a while, Twi. Maybe I should leave you two alone and come back tomorrow.”

"And go out in this weather?" Twilight cocked her head. "Rainbow, are you crazy?"

"Come on, you know I've flown through worse." Thunderball shot Rainbow a stern glance as the room was lit up as bright as day, followed shortly by a thunderclap that shook the books on the shelves. "...On second thought, it is kind of a rough night. Don't suppose you'd mind a sleepover?"

The proposal brought a warm smile to Twilight's face. "Sure, let me just get Slumber: 101."

Thunderball raised his hoof in mild annoyance. "Your Highness, I have sensitive information for your ears only. May I talk to you in private? Now?"

"Don't worry, you can speak freely here." Twilight casually levitated the book down from her bookshelf. "I trust Rainbow."

Thunderball gave her a skeptical look for a few moments before finally laying out dozens of photographs on Twilight's desk. Many of them depicted scenes from festivals across Equestria in the past year. Twilight had attended some of them and could occasionally spot herself along with her friends. In each photograph, ponies had been circled who closely matched one another, down to their cutie marks.

Twilight urgently leafed through the evidence until she had covered the desk in photographs and reports. "Are you telling me that changelings are still impersonating ponies in Equestria?"

Lt. Thunderball nodded tensely, but his voice remained as calm as ever. "It's been going on since at least a year prior to the invasion, Your Highness. Our intelligence analysts have been going over old photographs trying to see if we could spot any signs. So far, we can confirm that there are multiple changelings in Ponyville, which constitutes an imminent threat to your person. I was immediately dispatched to inform you of the problem and ensure your security." He gave Rainbow Dash a long, hard look. "I would respectfully suggest we start with Spike and the rest of your friends before working our way onto the general Ponyville population."

"Hold on a minute!" Rainbow's nostrils flared upon hearing the accusation. "You're the one who showed up out of the blue with this wild story about changelings infiltrating Equestria, but we haven't heard anything from Celestia herself about this, even though she could have just mailed a letter to Spike saying, 'Hey, watch out for changelings.' How do we know you're not a changeling?"

"Ma'am, if you're accusing me of being one of those da—" He caught himself mid–sentence and took a deep breath. "creatures, I would like to point out that their assumed forms lose cohesion when subject to extreme trauma or disruption, such as being struck by lightning."

Rainbow's eye's narrowed dangerously as she stepped close enough to Thunderball that their reflections became mirrored in each other's eyes. "According to the reports you gave us? Yeah, really rigorous proof there."

Twilight stepped between them and shoved the pair apart. "Break it up you two! Look, Rainbow, I appreciate your concern, but you don't have to be so worried. There's a very simple spell to determine if the lieutenant is a changeling or not. I used it during the changeling invasion of Canterlot last year."

"Then cast away," Thunderball snorted, glaring at Rainbow Dash. Twilight's horn glowed purple for a brief moment. A narrow beam of violet energy struck Thunderball right between the eyes, and he collapsed like he had been hit by lightning again.

"Oh my gosh!" Rainbow rushed over to the stallion and helped him to his feet.

The aid was poorly received, as Thunderball pushed her away the moment his shaking legs could carry his weight. "So can we agree I'm not a changeling?"

"I'm so sorry about that!" Twilight pulled out an old spellbook from behind her and began rifling through the pages. "I had no idea that would happen. Something must have gone wrong with the differential of the containment field — the scalar vector of the sinusoidal carrier wave must require additional dimensional constraints in order to avoid arcane backlash. Not a problem in combat, of course, but for diagnostic use, it needs to have the exponential factor adjusted by a magnitude or more."

Thunderball exchanged a concerned glance with Rainbow Dash as Twilight poured out enough speculation to fill a doctoral thesis in quantum thaumaturgy. "It's fine, Your Highness. I've had worse."

Rainbow slapped him between the wings. "Yeah, like when that lightning bolt hit you!. Still amazed you came out of that in one piece."

The dialogue had the intended effect, as Twilight stopped her speculation mid–sentence to focus on what she had just heard. "You were struck by lightning?"

"Yes." Thunderball glared at Rainbow Dash. "Right after warning your friend to stay out of the skies in this weather."

Rainbow's wings shot up immediately. "Hey! Then how come you were flying around, hotshot?"

Thunderball raised his wings as well, his hair bristling. "Ma'am, I think you'll find that the military aviation code differs substantially from the civil one. If you ever bother to read them."

Twilight raised her voice, which stopped the dispute in its tracks. "Enough with the arguing! Don't make me turn that into an order."

Rainbow Dash blushed and scratched the back of her head with a hoof. "Sorry, Twilight."

Thunderball bowed to hide his embarrassment. "Apologies, Your Highness. But we still need to ensure that the premises are secure."

"I'll take care of it Lieutenant. Trust me, I've handled changelings before." Twilight tidied up the photographs with her magic and stuffed them into the envelope. "Well, if that will be all, I think it's high time we went to bed. Thank you for the briefing, Lieutenant. I'd like to sleep on this before drawing up a more comprehensive plan. Would you like to stay the night as well? I have a spare bed down in the basement."

There was an almost imperceptible pause after Twilight mentioned her basement before Thunderball responded. "That will be fine, Your Highness." Thunderball bowed again, but remained in the room standing at attention.

"Alright; don't hesitate to make yourself at home!" Twilight subtly gestured that Thunderball was dismissed. "Just don't mess up my book filing system!"

He saluted sharply, clicked his rear hooves together, and trotted out of the room. Rainbow Dash did her best to keep a straight face during all of it, but broke down the instant the door closed behind him.

"Wow. I knew royal guards were uptight, but that guy's something else."

"Actually, the Secret Intelligence Service isn't a branch of the Royal Guards at all. It's Section 6 of the Military Intelligence Directorate."

The definition drew a blank stare from Rainbow Dash. "Right...and the difference is...?"

Twilight slowly massaged her temples. "He's a spy, not a soldier."

Rainbow's eyes lightened up as she grasped Twilight's point. "Wow! You mean like Roger Maare?"

"...That is a fictional character, but yes."

"Cool! I wonder if he's ever ridden a jet ski over Neighagra Falls while being chased by zebras bent on replacing Princess Celestia with an impostor!"

"...That was the fourth Roger Maare novel."

"Well yeah, but I'm sure he does all sort of awesome super secret spy stuff!"

"Actually, most intelligence consists of analyzing information, not fieldwork. And even if he did have field experience, he probably couldn't tell you about it because it'd be classified."

"Wow, way to burst my bubble there, Twi."

"Sorry Rainbow. How about I get you some hot chocolate to make up for it? Extra marshmallows."

Rainbow licked her chops as she started to drool. "Throw in the new Daring Do book and you've got a deal!"

Meanwhile, in the basement...

Thunderball had walked onto the basement stairs and closed the door behind him. He immediately reached into his saddlebags, pulled out a bright flashlight, and swung its beam around cautiously before he located the lightswitch, which he pressed with indecent haste. Light soon flooded the basement, revealing all of Twilight's laboratory equipment, a small private library of scientific textbooks and reference material, and a cot she slept in when her research kept her up late at night.

After setting his saddlebags down by the bed, he wandered through the laboratory and collected as many lamps as possible. He picked up a power strip and plugged as many of the lights into it as he could before setting them in a pattern around the cot so that they'd illuminate the entire basement should the ceiling lights go out. After all, Princess Twilight had warned him against disturbing her filing system, not her interior lighting.

He hesitated before climbing into the bed. It was just a simple cot, but Her Highness had used it often enough that she'd left her indentation on the mattress and her scent on the sheets. Sleeping in the same bed as royalty would be awkward, but it would have been impolite to turn down the offer. He decided to compromise by removing the mattress and laying a sleeping bag over the cot's metal frame.

Thunderball turned on the lamps and was almost ready to settle into his sleeping bag before he noticed a curious device on the top shelf of Princess Twilight's personal science library. He smiled as he recognized it as a plasma globe and unplugged a lamp to make room for it around the cot. The electrode in the middle of the globe came to life and began to discharge purple plasma filaments into the glass sphere in a soothing display that gradually lulled him to sleep after a very rough day.

Author's Notes:

I have no practical knowledge of war, so I tried to do some research for this story. Unfortunately, due to time constraints, I was unable to watch videos, read books, etc, so I settled on listening to a lot of music, which is a fantastic medium for conveying emotions in the span of a few minutes. I'll be putting lyrics and links to various songs in the author's notes, either songs that remind me of the themes of the chapters, or which I just like.

O'er the hills and o'er the main
To Flanders, Portugal and Spain
King George commands and we obey
Over the hills and far away