When Twilight Sparkle found Applebloom waiting outside her door, she felt a wash of anger, followed by guilt. Her irritation stemmed from Applebloom's apparent refusal to listen, from her own foolishness in giving this mouse a cookie, and from the general milieu of a life she no longer herself led. Yet, in recognizing Applebloom's haggard resemblence to her once close friend, she could not help but devalue her own stake in the matter. She had a bed to sleep in at night and a steady if tenuous income, luxuries this young mare had lost through no fault of her own.
Thus, Twilight Sparkle prepared herself to be talked into letting the stray stay the night. But, to her surprise, it didn't happen. Applebloom didn't want to stay anywhere. Applebloom wanted to talk about magic. She wanted to talk about her last visit. In particular, she seemed absolutely fixated on something she alleged Twilight had said: that there was no spell to turn back time.
No, that wasn't it. Twilight had said there was no easy way to turn back time. And that was different, because it implied that there was a hard way. No pony who didn't think there was a way would waste her breath inserting the word "easy" where it didn't belong.
Twilight Sparkle did her best to explain. Using magic wasn't as simple as pointing your horn and grunting, contrary to any appearances. It was a science; every spell demanded exacting precision, a disciplined mind, and, above all, exhaustive research.
Yes, she had heard of a spell that could influence the past. But it wasn't time travel; you couldn't send ponies galloping through history, thank goodness. It was a persistent alteration in the fabric of space, a rewrite that would introduce some small new element to the cosmos.
But she had only heard of it. It would take all the vacation and sick days she had in a year to peruse the Canterlot library for such an advanced text, and that was only if they were willing to let her try. And even if she found it, she would never be able to cast it. Such arcane feats were the exclusive domain of the magical elite, those ancient unicorns who had honed their skills over millenia. Luna herself was probably the only pony left in all of Equestria who stood a chance.
And even if you had all the time, the books, and the personal assistance of Equestria's monarch, you'd still only be able to effect the slightest change in the past. Something so subtle you would hardly notice it if you weren't looking for it.
"You mean like giving the assassin a lazy eye?"
Twilight Sparkle reeled at Applebloom's reply. It was . . . plausible, but Applebloom was missing the point. Even if the spell worked as intended, it would be reprehensibly selfish. To save a diarch from a death already years old, to redirect the flow of Equestria's history, all for the fleeting hope that it might save one family of Earth ponies from destitution? She felt deeply for Applebloom, but they could not rightly move the world for what could callously be called a concedable loss.
Twilight braced herself for Applebloom to mistake her words for apathy, to rave at her indifference, and to mourn the death of a fairy tale ending. But she did none of these things. Instead, she recounted her time since their last meeting.
It was not the narrative Twilight would have expected. There was no mention of Applebloom's long, cold nights on the street nor of any other personal miseries, only a litany of Twilight's broken former friends. Many of their stories were not new to Twilight; she had heard of Fluttershy's betrothal to a noble, of Pinkie Pie's incarceration, and of Rainbow Dash's injury. But doubt had always given Twilight room to construct better circumstances for each of them; she had imagined Fluttershy a loving wife, Pinkie Pie a recovering repentant, Rainbow Dash a relaxed retiree. Had it been an unreasonable fiction for Rarity to have found a market, for Sweetie Belle to find her voice? First-hand testimony left no room for self-delusion.
Applebloom didn't argue for her own sake. Her determination stemmed from a loyalty that far outshone Twilight's, to friends that were ostensibly hers. The last denier in Twilight's mind belittled the entire appeal as a child's protest that life wasn't fair. But the pony before Twilight now was no filly; she had seen more of the world's depths than Twilight and bore more of its burdens than anypony ought. A flicker lit the dark spaces of Twilight's heart. It was time to relent.
Applebloom visibly brightened at this, but Twilight could tell she was containing herself. There was much yet to be done.
* * *
The library of Canterlot was cathedral to the written word. Monoliths of stone arches and endless shelves housed a (savvy) dragon's hoard of literature, from every past age, venerated author, and studied field. Two ponies could spend their lives reading only those novels whose titles started with 'A'; only the most discriminating pair could be dissatisfied with the selection.
Such was the opinion of the principal librarian, anyhow. Twilight Sparkle had more to say on the matter.
"As Celestia's apprentice, I was granted access to every wing of this building, even the catacombs you've been told not to mention," she said mightily, "There is no power short of another princess that can deny me that privilege. Or has Princess Luna commissioned your services in opposing her late sister's students?"
The display astounded Applebloom, who had never had so much weight to throw. It had an at least similar effect on the curator, who ground his teeth as he invited the pair to follow him.
The deep archives of the library lay behind twisting catacombs and daunting stone doors. The curator unlocked them and opened them under the augury of his luminous horn, but he did not follow them in. It was silent, save for the timid breathing of the intruders, and dark, save for the light of Twilight's magic. There were no bookshelves, here; instead, chests of drawers the height of two stallions stood watch over the crypt. Twilight Sparkle stalked over to the nearest drawer and creaked it open. Inside, a codex nestled cozily on a silk pillow and under a glass case.
"The library has tried to catalogue these books before," she said, off-handedly, "but the initiatives are never seen through. Too many books in too many dead languages and not enough experts qualified to sort them."
"So how will you figure out which one has the spell you want?" asked Applebloom, taking in the labyrinth of manuals.
"Slowly," said Twilight, paging through her first victim. She studied passages, first at random, then seeking with specificity. Applebloom fidgeted, wandered to the edge of the light, and wondered how far beyond it lay the far wall. At the conclusion of several minutes, Twilight closed the book and gingerly replaced it.
"Okay. One down."