Twilight was tired.
Staying overnight, awake in a massive stone castle researching will do that to you.
Yesterday, she had came across an interesting concept during a conversation with Pinkie Pie.
"And then I wondered, what makes it a perfect day? The skies are bluer, the clouds are..."
The rest isn't important. Twilight couldn't believe that she hadn't thought of it before, though. She had wondered to herself for a while back in her castle for a while before deciding to research the subject.
"What does make a perfect day," she had asked herself, "to arrange everything so perfectly that nothing could go wrong? Would it be perfect if you had to set everything up beforehoof?"
It struck her. The perfect day required a perfect world. What was more perfect than harmony? And thus, she packed her bags, alerted Spike, and left for the Everfree the next morning.
It was a day later. She hadn't made any progress quite yet, but surely the next tome, surely the next passage...
Upon lifting the next book out from the library, she found it was stuck. Looking closer, one of the cold iron bindings appeared to actually be stuck to the bookcase. Pulling harder, the entire wall behind it gave way. "Waaaugh!", she yelled, backing off fast as an entire wall section came down right where she was standing. When the dust was clearing, she noticed an odd black stone floor passage.
That's incredibly odd, she thought to herself. This stone appears to be pure onyx, and I don't think I've seen it before. Deciding against her screaming common sense, she proceded into the tunnel, horn shining with magical light.
