Princess Twilight Sparkle discovers a centuries-old mystery hidden in the Royal Archives. Her investigation leads through layer after layer of deception and misdirection, setting her hooves on a path that seems to be leading to a mysterious secret. Along the way, she learns that some friendships can be very, very strange.

Book 1 of the Alicorn Adventure series.

AUDIOBOOK by VisualPony
Featured at the Royal Canterlot Library
TV Tropes Page (Courtesy of Sandtalon)
Goodreads Page (Courtesy of Facedeer)
Equestria Daily Page

WARNING: Major spoilers in the comments. Takes place several months after the end of season four. (Not a Da Vinci Code crossover, BTW!)

Do you see a dark tag? No, you don't. Not dark. Well, okay, there are a couple of dark-ish bits, but that's all. Not enough to warrant a tag. Speaking of tags, there really ought to be "Badass Twilight" and "Friendshipping" ones.

Sequels and side-stories (and more) can be found here Offprint and AO3, and a hardbound two-volume set of all that can be ordered from The Ministry of Image.

My editor for the first edition of this story was Gogito, and I can't thank him enough for all the hard work he did. My editor for the revised version was PresentPerfect, and he did a terrific job of getting the story into excellent shape.

When Celestia went on sabbatical into the west, she promised Twilight it would be only a couple of months. A year and a half later, the sun resists control, the country is in ruins, and her teacher is lost in the wilds. Twilight has become the apostate, her faith in her teacher and her teachings waning. In the wake of tragedy, her resentment blossoms into fury and she vows that something must be done. Shadows gather around Canterlot, and old things that should not have been awakened are on the move. The Student goes west, her hope restored by friendship and righteous fury.

The night, at long last, is passing.

"... at the forefront of our fandom’s writing scene ... Masterpiece." —PCaRG
"... really enjoyable ..." —City of Doors
"...worthy of high praise." —PaulAsaran
"Lots of wonderful world-building, great action, well-developed characters and an engaging story." —Hoopy McGee

Steel Song is a lot of things. Earth pony. Uncle. Professional bodyguard.

Retired.

So when he receives a mysterious package from Princess Luna a few weeks after the changeling invasion, he's understandably apprehensive. More-so when he presents himself before the Royal Diarchs to find that not only do they desire him to come out of retirement, but to take command of a most unusual position...

A position that may have more significance than any of them suspect. Because strange thefts are occurring on the Equestrian Railway, thefts that nopony can explain. Thefts that may have far more sinister intentions than their seemingly innocent nature may convey.

Intentions sinister enough to shift the balance of power in Equestria forever.

Book I of The Dusk Guard Saga.
Epic Fantasy
Has a collection of Side Stories as well, the first of which is here.
Now with a TV Tropes page!
"This is 100% Approved by Twilight's Library!"
Added to Twilight's Library 11/26/2013
Added to Canterlot's Finest 12/01/2013

Now Featured on Equestria Daily!
TV Tropes and a group of its own.
Audio version
( EPUB / MOBI )
Three Nights in Manehattan, a sequel
Hardcover Print-on-Demand Order Page

As a child, Daphne knew of a world where magic lived, where an immortal princess reigned over a beautiful kingdom, and longed to journey there beside Leit Motif, the filly she'd grown to love in the woods behind her home. But one day, when she needed her most, Leit Motif was gone, and she never came back to show her the way. As she grew, she put aside her childish dreams, and taught herself to believe the lie.
When forces beyond her knowing take her sister Amelia, though, she discovers that her childhood fancies were entirely too real, and is thrust into a journey that will take her back to that land she longed for, back to the childhood friend she'd abandoned, and to worlds she'd only dreamed of.

Interview with Pre-Reader Amacita
PresentPerfect's Review

[Complete! With TVTropes apparently!]
Also, apparently, an animated trailer.

In a world of brass and steam, Twilight Sparkle had thought she had made a life-changing discovery with the invention of the telescope. For better or worse, she was correct.

Now her discovery has not only changed her life, but the lives of those she seeks out in her desperate attempt to contact the only other creature as lonely as Twilight herself.

It all would have been much simpler, but it had to be the one Twilight could only call The Mare on the Moon.

Decidedly not within walking distance, then.

[Featured on EQD before story was meant to be submitted. 4/03/2015]

[Editing team: Southpaw, Wolfvenom, Maskedferret, SwanSong and BluePaladin42, without whom this story would be a fraction of its current state.]
[Special thanks to Novel-Idea for the updated cover]

This story is a sequel to Utaan

Rainbow Dash traverses the perils of the Dark Side of the world to reach the Midnight Armory.

Cover art by Dafaddah