Ravens are the traditional guardians of the White Tower, the medieval fortress at the heart of London. They say that when the ravens leave the Tower, it will mean the Empire has fallen...

On that morning, I woke up before sunrise, perched next to my sister Ruby. We lived together in a small house then, a comfortable house made of wire where our Keepers fed us and made sure our wing feathers stayed short. The yard between the four stone walls was our whole world, and we appreciated the attention that the humans gave us.

It was three days before the shortest day of the year. I remember because it was cold, and the humans were hanging pine branches on the stone walls and singing songs. I sang along quietly, copying their sounds with my agile vocal cords. I always loved human songs, and I was the best singer in the flock. Completely modest about it as well.

"Mercy!" Ruby squawked to me, waking me out of my reverie. "I had a terrible dream where the Keepers left us."

"Calm down," I told her, smoothing down the feathers on her wing. "It's only a dream." No Keepers? The thought terrified me. The Keepers protected us by clipping our wings and giving us these houses to live in.

Ruby opened her beak but said nothing. Together, we hopped down from our perch and out into the yard. A thin blanket of snow covered the grass. Stuart and Edward, the two youngest ravens in the flock, took turns fluttering their wings and blowing snow into each other's faces. Cullinan watched them from a distance with his one good eye, too shy to join in as usual.

"Good morning!" I squawked as I hopped out onto the snow. Usually I climbed atop my favorite rock, but the stone felt uncomfortably cold to my talons on this day. "Where's Elder Koh?"

Stuart grunted. "In his nest, as always, the cranky old bird."

"Can't have our flock leader sleeping in on this fine morning!" I hopped to the elder's house and entered in. He wasn't sleeping but rather huddling in a corner of the wire house, staring at a spot on the wall. I felt rather sorry for him. He must have been so cold without any relations to huddle with.

"How are you today?" I asked cheerily. Instantly, I regretted it.

Koh turned to me, an ominous look on his face. "The winds of change blow," he declared. "I have heard it whispered on the dark moon and the white snow."

"Come on," I told him. "Are you sure that wasn't just the human metalbirds? They come more frequently this time of year."

"The sun will not rise this morning," he said. "We will not see it for days on end."

"I should think not, with these clouds covering the sky. Thick and dark as Cullinan's wing feathers, they are!"

"A new sun will rise. A sun of blood and fire."

I left the elder's nest feeling deeply unsettled. I ran my beak through the snow, feeling its cold crystals. I swallowed one. It tasted like nothing. Out of the corner of my eye, I saw Cullinan watching me and shaking his head.

As minutes turned into hours, the six of us gathered atop the stones to try and watch the sunrise, cloudy though it was. I couldn't stop thinking about what Koh had said. Relax, Mercy, I told myself. It's just another crazy omen. He sees them all the time.

But as we waited for the sun, my gizzard twisted--first into dizziness, then unbearable nausea. Something was wrong, and I couldn't place what.

Then the whole sky lit up, a huge wall of golden fire burning across everything we knew. A wave of pressure crashed over us, a roar louder than the loudest thunder, then complete and utter silence as it ended, just as quickly as it had started. The snow returned, falling lightly from the sky onto the yellow-brown grass and our feathers.

Not snow, I realized. Ashes.

We were never going to see our Keepers again.