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// Castle Mane-ia: Organ Donors Wanted! 
// Story: Letters from an Irritated Princess 
// by Tired Old Man 
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My dearest Twilight,

While it would be perfectly lovely to have you in Canterlot once more, I have another option in mind much closer to Ponyville.

See, after hearing your very laborious and long-winded request to look at every single text in every single library in Canterlot and the forbidden tomes, even the one known to eat faces upon opening it, I realized you were quite serious about looking into this lockbox. Probably far too much for your own good, but I know that once something catches your interest to the point of making this kind of request, it's difficult to get you back to ground level without waving Smarty in your face, or in extreme cases, using a laser pointer.

Anyway, I checked my library, your old one, and Starswirl's archives. I even had Luna sort through hers and asked the Royal Canterlot Librarian to sift through the records on anything that might have been submitted on the Tree of Harmony and its origins.

Fruitless endeavors, I'm sad to say. We found absolutely nothing beyond a small recognition of the tree in a history book about it being the original host of the Elements of Harmony, but that's all. My field researchers may have the balls to get up close and personal with dragons, but they mysteriously vanish the moment they hear the word "Everfree."

That's where my other option comes in. As you know, the ancient castle that I once shared with Princess Luna lies mostly in ruins, deep in the Everfree Forest. But if you look carefully, you may find a book that could prove helpful to your research, hidden somewhere in what's left of the castle library.

Key word: "may." There is no guarantee, but the texts that remain there are far older than what's on record here, so it's your best shot for looking into that lockbox.

Heed my warning: Luna and I never got around to disabling some of the trapdoors and secret passageways built into the foundation and first floor, so you might encounter a few hazards as you explore the castle. Don't ask me why we put in so many--it's a long story involving a short-term plan to dispose of dissident nobles that backfired heavily once we discovered we couldn't just treat them like trash, even if they treated others that way.

Barring that, if you're still determined to look into this box, then by all means, raid the remnants of the castle. Just make it out in one piece and respond once you're out of there. 

Best of luck,

Princess Celestia

Luna, could you come in here for a moment? I have a question.

Now, it's normally not my business to ask about your spending habits, but may I ask exactly why you bought ten thousand Lunacanes?

Don't tell me you didn't! Your signature is right here on the order form! You even bought a giant stuffed Ursa Minor sitting in the giant crate I put in the throne room! It even made realistic growl noises!

Look, I don't care if you ordered these or not, I signed for the delivery, and these things have your face and name all over them. This is YOUR problem to deal with, not mine.