"Well, that sure didn't work."
I shoot bolt upright. "What did you say?"
Spike blinks. "Uh, well, I just meant I don't know what you cast, but I'm pretty sure Starswirl the Bearded never wrote any 'blow-up-in-your-face' spells. Are you okay?"
I stagger forward — I'm long since used to the pain by now, but there's always a moment of adjustment at the start of a new loop as my consciousness reassembles itself, screaming and flailing, and reorients into a body that hasn't been clawed apart or mashed into pulp or disassembled into its component molecules by explosions. I clamp my hooves around my faithful assistant's shoulders and shake. "WHAT. DID. YOU. SAY?"
Spike yelps and cringes. I take a deep breath, close my eyes, and force myself to start over. I've long since grown tired of wasting time explaining things to others who will forget it all the next time the loop resets — but this is significant enough to be worth talking out in order to give me a chance to sort through my thoughts.
"I'm sorry, Spike," I say. "Listen. The spell you just saw me cast stuck me in a time loop — I keep getting reset to this exact moment over and over again." I wave a hoof around the restricted section of the Canterlot Library archives, where I'd found Starswirl's spell and been so overwhelmed by curiosity that I'd chalked an evocation circle in a back room to try it out. "Under normal circumstances, this would be the best possible thing, right? Getting the same block of time to experience over and over again, here in the largest library in the world, with all of Canterlot outside the door; and if I ever get bored of the ability to infinitely devour knowledge without aging, I can go ask one of the princesses for help getting things back to normal."
Spike looks at me blankly. "Uh, Twilight, are you sure you didn't maybe hit your head a little hard there?"
"But there's a catch," I continue. "I just so happened to cast the spell right at the cusp of a new changeling invasion. Queen Chrysalis is minutes from replacing Princess Celestia in a surprise attack, there’s the world's biggest swarm on its way here in less than an hour, and the palace staff and Royal Guard have been thick with infiltrators for months. As if that weren't enough, in about three hours the Elements of Harmony will overload from the negative energy of all the death and destruction of their attack, and blow the whole world up."
His jaw is hanging open. Now he's staring at me with a mixture of disbelief and horror. I feel a brief twinge of regret for shredding his innocence — yet again — but it's not like he'll remember it next time the loop resets, and it's hardly the worst thing I've done while trying to singlehoofedly accomplish the impossible task of saving Equestria.
"I've been trying to stop that for … several hundred? … loops now," I say. "Nothing changes from loop to loop except for the knowledge I have from the previous ones. Everything is absolutely identical except for what I myself alter. And without fail, every single time, I've woken back up to four little words."
He points at me, then brings a claw to his chin. He squinches his eyeridges together, staring at me. His jaw works soundlessly. "… Well, that sure didn't work?" he finally manages.
"Spike, that's FIVE."
"Twilight … your fur is still smoking. Maybe you should sit down and —"
"Why did you say 'sure'?"
"Because you sure blew yourself up! You're scaring me, Twilight. Please sit down and I'll go get a doctor." He dashes out of the room, his stubby legs a blur.
I rack my brains. Did something tangible from my last loop carry over to this one? All I did was grab the Elements of Harmony from their vault and hop on a train, trying to test whether removing them from Canterlot would prevent their explosion so that Celestia wouldn't have to spend all her focus on keeping them calm. Well, as it turned out, that didn't work. But it must have done something. I know I heard that extra word, and I know there's no way I could have reacted differently enough in the split-second after resetting to change his speech.
I take a look around the library. Really look, in a way I haven't done in subjective months. If there's a book out of place, if there's a line chalked differently in my circle, then I can't see it. The air does look smokier, I guess? No — that's confirmation bias. Spike just told me I was smoking, so it's exactly the sort of claim I could convince myself of without evidence. I could take samples and measure the composition of the air, but … no, it would take me too long to find sensitive enough equipment, not to mention if something has changed I don't have a baseline measurement from previous loops.
Instead, I teleport in a series of hops up to a nearby observation tower, hoping that there's something to learn by getting a view of the library from outside. I give the city a cursory glance over my shoulder, and my jaw falls open.
There's no swarm approaching Canterlot.
No — wait. There they are. They're a black fuzz out on the horizon in the direction of the Everfree. They've never been this far away, and I've come straight here any number of times. I glance over at Big Pen, but the clock on its face is at the same 3:13 that every loop has started with.
This is completely incomprehensible, but I don't want to look a gift pig in the mouth. Did something happen to delay the changelings' plans? Then that might mean …
I've teleported down to the hallway in front of Celestia's private chambers before I can even finish the thought. There should be a full platoon of changelings here disguised as Royal Guards, while Chrysalis overpowers Celestia inside. But the hallway is empty except for Sharp Edge and Parade Rest standing by her door.
Sharp blinks. "Twilight? What's —"
"National security emergency. Today's validation code" — learned in one of my earlier loops trying to figure the best way to muster the Guard — "is 438 hay-roan-zebra. I'll be inside. Nopony else comes in."
Sharp salutes, but hesitates. "Nopony at all? Not even —"
"Okay, you can let us know if the building's on fire around us," I joke, giving him a disarming smile. "Don't worry, we'll be as quick as we can. Also, call Blue Glow — she's the battlecaster from Barn Company — to lay down an anti-transmutation ward on this hallway, and then get 114th squadron here to back you up." The 114th is changeling-free. I'll need them elsewhere later in the invasion, but right now I want trustworthy ponies here. I get two salutes in return, Parade wingsprints off, and for the first time in many, many loops I feel hope stir in my chest.
Celestia is sitting at her desk when I barge in, elbows up on the smooth white marble, resting her muzzle on her pasterns and staring unfocusedly into space. She looks up at my arrival and forces a smile. "Twilight," she says, faltering for a moment, "I'm sorry you had to hear —"
I stride up. "No time for apologies. Chrysalis is in the castle, there's a changeling swarm on the horizon —" I blink. "Wait. Had to hear what? This is the first time I've seen you this — today."
Her eyebrows furrow in thought. "At Court … the stallion who came up to the two of us and …" She stares at me. Her eyes widen as it all clicks together. "Chrysalis was you. Of course! Twilight, I hope you don't mind if we cast changeling detection spells on each other?"
I don't mind. We both come up clean. She sits in front of me, staring down at me with an intensity I rarely see. "Tell me everything you know, Twilight, and we'll fix this."
"'Everything' would take a while. I'm stuck in a time loop —"
I stop because her hoof is jammed in my muzzle. She leans in. "In that case, wait." She closes her eyes. Her muzzle shifts as she subvocalizes some words. I feel the wrench of magical activation, even though her horn doesn't glow. However, whatever it was she triggered dissipates without any apparent effect. She opens her eyes again; a dim light in her pupils is fading away.
"If we don't get things right on this pass," she says, "then the next time you meet me, tell me the phrase 'preengaged blackout deharmonizes antihunting dissertation', exactly as I just spoke it. Have you got that?"
I repeat it to myself a couple of times. "Yes."
"Out loud, just so we're sure. It's neutralized now."
"Preengaged blackout deharmonizes antihunting dissertation, right. What does that trigger?"
She smiles inscrutably. "Tell me in another loop, and you'll see. What's our tactical situation?"
I give her a brief summary of what I've learned over the scores of loops spent teleporting in between the various Royal Guard units. She listens attentively, asking good questions, and leans back in thought when I'm done. "It sounds like we have the numbers to repel them," she says, "as long as the infiltrators can be dealt with before the swarm arrives. Have you tried taking this information to the Guard commanders? Do you need today's validation code?"
"Actually, I've never had time before. That's the weirdest thing about this. When I started this loop …" Something tickles at my nostrils. "… Do you smell smoke?"
The door bursts open, and Sharp Edge and Blue Glow gallop in. "Princess, Mistress," Sharp says hurriedly, "I'm sorry to interrupt, but the building's on fire around us."
My jaw drops. "Wait, are you serious? Because, for the record, I was joking about that."
"There are at least four separate fires throughout the castle, including a small one right downstairs," Blue Glow says. She points a hoof toward the window. "The main blaze is deep in the East Wing. You can see fire in some of its windows from here."
If the infiltrators moved before we did, then this loop's a bust — but I can still gather information for the next one. I note the time — 3:46 — then gallop over to the window and look out into the courtyard. I see smoke over the East Wing, but not the fire itself. "Where?"
Blue joins me, putting a hoof around my withers and drawing me in so I can see down her foreleg as she points at a window semi-obscured by a tree in the courtyard. A squadron of Guard pegasi is surrounding it, hauling in a chain of rainclouds, shouting orders and sending civilians scurrying every which way.
I squint. "Hang on," I say. "That's the 114th. Who's out in the hallway?"
Blue freezes for a moment. Then she grabs my neck and wrenches. I hear a pop.
Celestia gasps as I crumple to the ground. "Chrysalis!" My vision blacks out amid her laughter.
* * *
"Well, that sure didn't work."
I leap to my hooves. Oh, it is on. That's the first time in over a hundred loops that Chrysalis has killed me, and it is going to feel so good setting that right.
"Unless Starswirl the Bearded wrote a 'blow-up-in-your-face' spell —" is all I hear Spike say before I teleport to the hallway in front of Celestia's room. I give Sharp and Straight the same orders, word for word, and dash inside.
Celestia is staring unfocusedly into space again, and gves me the same forced smile. "Twilight," she says, faltering for a moment, "I'm sorry —"
"No time for apologies. Chrysalis is …" I've gotten so good at putting my brain on autopilot and repeating my actions from loop to loop that I almost forget. "Hang on. Last loop, you told me to tell you: 'Preengaged blackout deharmonizes antihunting dissertation.'"
As I finish speaking the trigger, a wave of energy bursts out from her. Pain lances through my head, and my muscles lock up. I can feel my horn spark with magical feedback and my body go numb. The world goes grey around me, and as I topple to the floor, I hear two muffled thumps out in the hallway.
Celestia — who is still moving — steps forward. She looks at me dispassionately. I feel a vague pressure on my chin as she caresses my muzzle in her hornglow.
"I hope that you weren't manipulating my mind, Twilight," she says, "and that you truly are in a time loop, so that next time you can add the safeword 'coruscating' right before the trigger."
I try to protest through the paralysis. I can't even breathe. My lungs are starting to burn.
Her horn flares. I hear a familiar pop.
* * *
"Well, that didn't work," a familiar maternal voice says.
I sit upright, head swimming, to find Celestia standing behind Spike at the edge of the evocation circle.