Excellent new chapter. I love how you where able to let Fluttershy use her animal communicating abilities.

A phoenix! I was sure of it! But where was the sound coming from?
 
My vision slowly faded from blinding white to a dull grey. My eyes strained, trying to find the exotic bird. I twisted my head left and right, taking in my surroundings. A rocky wall to my right towered into the mist, and a grassy ledge to my left opened up to a vast expanse of fog and sheer drop below. This was the road to Canterlot, along the sheltered side of the mountain.
 
If I’m here, then that means… My gaze drifted to my hooves and caught sight of my chest. I don’t have my Element yet.
 
Wait. I’m remembering my journey to Canterlot!
 
The dense fog gave way to a piercing gold light, and like a shooting star it flew overhead at great speed. The phoenix let out another cry, this time in triumph, as its blazing form curved around to land. My jaw fell open at the sight, and not a muscle twitched as the large bird extinguished its flames, and landed on my back with a hunter’s precision.
 
Warmth radiated from the phoenix, chasing away the mist surrounding us, and bathing me in her gentle glow. She looked relieved, and gave a quiet coo to me.
 
“Philomena?” I whispered.
 
She nodded to me.
 
My heart leapt up in my chest. “It really is you! What are you doing out here? Did Princess Celestia send you? Are my friends okay? Is everypony safe? Does anypony know what happen-”
 
Philomena screeched for me to hush, and raised a talon toward me, showing a capsule attached to her leg, emblazoned with Princess Celestia’s Cutie Mark.
 
“A message?” I frowned as the phoenix hopped off my back. She looked at me and nodded, and I carefully opened the capsule and pulled out the rolled up parchment inside. Before I unravelled it and started reading, I pulled an apple from my saddlebags and gave it to Philomena to thank her. She sliced into the fruit with her beak and started munching ferociously. When was the last time she ate?
 
I pulled my stare from Philomena, and carefully unrolled the message. Before I had even revealed the whole message, I was already processing it.
 
My Dearest Cadence,  
Please have your subjects search the library again. I know that we’re close to solving this mystery, but I fear that time is not on our side. Send Philomena back with any information you discover.  
Kindest regards,  
Celestia.
 
This didn’t make any sense. Why had Philomena delivered this to me? Princess Cadence was in the Crystal Empire as far as I knew. And I wouldn’t be able to reach the Crystal Empire any faster than a phoenix, or a dedicated Pegasus messenger – even with a tail wind.
 
I raised my head up to look at Philomena, who had rapidly reduced the apple to a core. She turned her head to me, her eyes warning of bad news. I almost abandoned my question before I started it.
 
“Philomena, when did you leave Canterlot with this message?”
 
The phoenix let out a saddened cry. Eight days ago.
 
That was the day before the spell struck. I could feel my stomach wringing itself as I spoke again. “Did you reach the Crystal Empire?” I asked, to which Philomena nodded in response. “When was that?”
 
Her fiery eyes lost some of its heat. Seven days ago.
 
“Did you see a shock wave sweep over Equestria while travelling there?”
 
Philomena nodded, and let out a series of short cries. She didn’t turn back when she saw it. She came back after finding the Crystal Empire without any ponies, after waiting in case somepony showed up. Philomena returned a day ago, her message undelivered until now.
 
I nuzzled Philomena’s beak, trying to hide the suffocating feeling in my chest. “It’s going to be okay, Philomena. I-I’ll get to the bottom of this.” I lifted my head up and looked upon the road leading up the mountain. “Or maybe the top.” I tried to chuckle, but it came out as short gasps. My eyes welled up.  
Deep breaths, Fluttershy, stay calm.
 
“We’re going to Canterlot.” I said evenly, brushing my bandaged leg over my eyes.
 
Philomena leapt up and screeched in alarm. Canterlot wasn’t silent like the rest of Equestria; it was overrun with strange creatures. When I asked what the creatures were, Philomena struggled to describe them, eventually settling on “Big dogs that walk on two legs.”
 
I thought of the hound I fled from in Ponyville. I thought of how his massive claws came inches from slicing me in twain. I shuddered.
 
“We can get past them if we’re careful.” I assured - more to myself than to Philomena.
 
Philomena shook her head. There was more. There were Dragons, too.
 
A familiar lead ball dropped into the pit of my twisted insides. I swallowed down what was pushed up.  
I looked directly at the phoenix, and shakily said “I have to go to Canterlot. My friends are stuck in there and need my help. I can’t let them down.”
 
Philomena unfurled her wings, her body of striking reds and oranges shimmering and glowing brightly. She tried to reason with me; if she went, they would see her. Both Dragons and Diamond Dogs had chased her out of Canterlot already.
 
“I understand, Philomena. Could you wait for me somewhere?”
 
She shook her head at me, pointing an extended wing into the mist with a screech. Snow front moving in. Too harsh for a phoenix to weather.
 
I stared off into the grey sky. I pointed my ears to the breeze and felt it nip at the tips. The temperature was colder than it had been, but I couldn’t believe that winter weather would be coming before Fall had even started. I didn’t want to argue, though, I was running out of time to reach my friends before something happened to them.
 
I wish it didn’t have to be this way.
 
“Are you sure you can take care of yourself, Philomena?”
 
The Royal Bird closed its wings and nodded deliberately. She was confident, or good at keeping things secret, because I thought I saw her shiver. I looked down at my hooves, noticing the unravelled message waving in the breeze, and began rolling it back up.
 
A thought popped into my head.
 
“If you ever change your mind,” I said as I placed the message back inside the capsule. “And the weather allows it, you can head for the old castle ruins in the Everfree Forest. I spent a night there, and it isn’t too far away from Ponyville – just be very careful of the Timberwolves, okay?”
 
I ran my hoof under the rare creature’s jaw, thankful for the few moments of company since the disaster over a week ago. I felt my mouth curve into a reassuring smile, and thoughts of being brave and hopeful followed.  
Philomena saluted with a wing and took off into the mist, her body’s warmth quickly trailing after her. A shiver ran up my spine. Had the wind always been this cold?
 
I watched Philomena circle above, her body quickly igniting into a molten orange that shone through even the thickest patches of the mist. I followed her with my eyes until she disappeared entirely from view.
 
Alone again.
 
I turned to face the path to Canterlot, if I kept a quick pace, I could reach the city by nightfall. If the city was that overrun by Diamond Dogs and Dragons, then the darkness and buildings would help me slip past them all. I would find my friends soon, and together, we would find a way to solve this.
 
What about Princess Celestia? Would she be there?
 
I couldn’t imagine her letting Canterlot be invaded by Diamond Dogs or Dragons, but if it was just her, Princess Luna, and my friends in Canterlot, perhaps she wouldn’t have had a choice. And because of the Dragons, Philomena wouldn’t have been able to find the Princesses when she returned, and couldn’t say if there was anypony in Canterlot other than the Diamond Dogs in the streets.
 
What did those Diamond Dogs want? What did the Dragons want? Who or what had caused that powerful spell in the first place? I wanted to know. For the first time in my life, I felt the pull of curiosity lead me. Ushering me on to Canterlot, to a definitely dangerous place, and I was okay with that.
 
I need the truth. I thought, though a pang in the back of my mind warned that it was different truth I was searching for. It warned of a truth that was driven much more by morbid curiosity, rather than fearless desire. I blinked away the thoughts, and my attention fell to the present.
 
I took a deep breath, and started to trot up the misty path.
 
I had to get to Canterlot.