Applejack, Spike, and Pinkie Pie spent quite a bit of time and effort helping me do research in the main branch of the Kingdom's library (I love, love, LOVE this place). Unfortunately, it didn't take long to confirm my suspicions: a metal cap wedged against a broken horn prevents the growth of new velvet, and as such the horn itself cannot grow any further. Cadance has to know this already. Rarity mentioned wanting hers to grow back, and she isn't wearing a fashion-friendly insanity horn cap of her own, but I doubt that means anything. Nopony has any clue what Rarity's game is in all this.

I sent Spike out to find Rainbow Dash so we could regroup here and share what we've learned. Dash is still certain that Fluttershy is hiding something under her wings, but neither Fluttershy nor Rarity are doing anything openly weird today. While we're all together in neutral territory, I thought it might be useful to slow down and write out the list of events again, because that thing that's been bugging me is still at the edge of my mind. So I'm writing this entry in the library itself. Everypony in the Herd of Five (Spike counts now) knows about my invisible ink, and that's okay.

Backtracking to the very beginning may have already paid off: Rainbow Dash says she remembers seeing a pegasus pony flying in the general direction of Fluttershy's cottage at night, sometime shortly before Fluttershy left for the Crystal Kingdom. It was too dark and distant for her to make out any details, but at the time she wondered if someone was headed out there to keep Fluttershy company that evening, since she'd been so depressed lately. Rainbow Dash asked Fluttershy about it the next day, but she said she'd had no visitors that evening so Dash just put it out of mind. Maybe it's a clue, maybe not. But here's what we know so far:

Day 0: Discord banishes Tirek

Day 1: Discord leaves forever (or so he says), Fluttershy becomes depressed

Day 10: Fluttershy doing better, visiting Mac (I now assume) at Sweet Apple Acres

Day ~14: Applejack notices some apples have gone missing, probably a red herring

Day ~17: An unknown pegasus may have visited Fluttershy's cottage in the evening

Day 19: Fluttershy very excited and happy, and leaves for the Crystal Kingdom to s-

Yes! I finally remember what's been bugging me! Fluttershy said she had "personal business" with Princess Cadance but she never told any of us what it was! Ugh, I'm such a dope! How the buck did I miss that? I just now asked everypony: Applejack and Spike hadn't spoken with Fluttershy directly, Pinkie Pie doesn't remember her exact words, and Rainbow Dash was told she was simply going on a trip to visit Cadance. I'm probably the only pony she said "personal business" to. I really wanted to ask her at the time, but I was going to wait until she returned, and then I guess I simply forgot all about it. Oh, wow. That's a huge weight off my mind.

We're going to have to be really careful. I want to press these points in a subtle way to see if I can finally catch someone in a lie without revealing my hoof in the process, and we're still right on the border of discovery. Every excuse is more farfetched than the last, but the house of cards is still just barely holding up... (I hate to admit it, but if I weren't so worried about my friends, this might actually be fun.) Anyway, I'd better finish the list:

Day 20: Fluttershy arrives in Canterlot, stays a half-day, sees Spitfire, and does ?????

Day 21: Fluttershy arrives in the Crystal Kingdom

Day 23: Cadance sends first note saying Fluttershy isn't around

Day 24: Speaks to Cadance or Shining Armor; Cadance sends emergency note

Day 27: Fluttershy leaves for home, does not stop in Canterlot

Day 28: Fluttershy arrives in Ponyville

Day 29: Hay loft sleepover; I probably get bites here

Day 32: I cast Cure Magical Bites

Day 33: Fluttershy sees me, asks me how I am, seems concerned about bites

Day 35: Rarity's horn missing, she doesn't seem embarrassed or to even care

Day 38: Luna warns me about Cadance's dreams "for many days now"

Argh, why was Princess Luna's warning so vague? Well... "many days now" is consistent with Princess Cadance being fine up until Fluttershy's (possibly unannounced) arrival in the Crystal Kingdom. I still see no reason to question that. All five of us considered the Flutterbat possibility, but I know the magic involved (I mean, I invented it for buck's sake) and even if for some reason she has the ability to revert back to Flutterbat, she shouldn't be contagious except possibly (and this is a very slim possibility) to other pegasus ponies. Plus, being a vampire fruit bat pony (which I suspect is very similar to a nightwing pony, but I can't find any information about Luna's guards or anything else bat-pony related yet) makes you animalistic and crazy and hungry for fruit, and that's it. It doesn't make you chop off horns or any of the weird things that have been going on.

Nonetheless, I cannot avoid noting something. Applejack has reminded me that the bites I received were, in retrospect, exactly what one would expect from a Flutterbat. Er, I mean, the Flutterbat. Or just Flutterbat. (Whatever.) It's still a stretch, because if Fluttershy were still magically affected, I doubt she'd even be aware that she'd bit me in the first place. Then again, the bites did make me feel very strange and antsy and itchy in a way I simply cannot accurately put into words. I've never had that kind of annoying, tugging, inescapable feeling before in my life. It certainly had nothing to do with apples.

Dammit. I kind of wish I'd waited just a little longer before casting that spell on myself.