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.

It was Ruby that came up with the idea, wings aflap and startled by the sound, even more so by Edward and Stuart’s laughter and insistence that this was the coolest thing they’d ever seen.

I could hear her wailing and crying even from inside Elder Koh’s nest, wings spread like a great jet beast. I poked my head out and she immediately turned towards me.

“Oh, Mercy! It was true! We shall all surely die now!”

I tried to look at her too, which was tricky given that her head was nuzzled atop mine.

“Ruby! We shall be fine, besides…”

I was interrupted by Stuart’s squawks. “Ruby! Mercy! Elder Koh! Come look at our Keepers!”

We all rushed over to where he was perched, right on the edge of the tower, talons clinging to the stone as he leant as far forwards as he could go. Below, lay a Keeper, or at least I thought it was, skin pink and red and shiny. Beside her, stood a shadow, burnt into the stone where he had been standing, but no Keeper himself.

Ruby began another bout of hysterics. “Mercy, see! They are all dead, and we shall be soon too, we must leave, we must flee—”

“Silence, Ruby,” Elder Koh said, finally awake and perched beside us without anyone noticing. “We shall leave, yes—”

”But Elder Koh,” I protested. “We can’t. This is our home, we are safer here.”

”Mercy. We are only safe here because of the Keepers. But they are gone. We are birds, and we can live perfectly well on our own. We must find what did this to our Keepers.”

”Yes!” Ruby squawked. “Yes, we must!” She flapped her wings, working the younger birds up into an excuted frenzy, calmed only when Elder Koh spoke again:

”But we may not fly. The Keepers have clipped our wings to keep us safe under the pretense that they will always be here. We shall be ambulatory creatures for as long as possible to prevent strain.”

Walking, it turns out, is a great deal harder than flying when you are built for the sky. Our claws were made for perching, not marching, and the six of us made an awkward procession down from the Tower walls, hopping and stumbling over rubble that had not been there the day before.

The world outside our yard was unrecognizable. The Thames still moved, sluggish and grey, but the bridges across it sagged like old rope, and buildings that had stood for centuries leaned against each other as if seeking comfort. Everything smelled of smoke and something sharper underneath it, something that made my eyes water and my throat itch.

"Keep close," Elder Koh instructed, though he needn't have bothered. None of us wanted to stray far. Cullinan walked at the rear, his one eye sweeping the wreckage, while Stuart and Edward had, for once, stopped their games entirely.

Ruby stayed pressed against my side the whole while, her feathers trembling. "Mercy, I don't like this. I don't like this at all."

"Nor do I," I admitted. "But complaining won't clip our wings back on, will it?"

We found no other living creature that first day. Not a pigeon, not a rat, not even the insects that usually swarmed the riverbank. It was on the second day, as we picked our way through what had once been a market street, that we heard it: a voice, hissing at someone to be quiet.

Elder Koh froze. We all froze, six ravens standing stock-still in a ruined street, and I confess my heart hammered so hard I feared it might give us away on its own.

Then a face appeared from behind an overturned cart. A child's face, streaked with dirt, framed by hair badly in need of a wash. She could not have been more than nine or ten. Her eyes went wide at the sight of us.

"Ravens," she whispered, not to us, but to whoever crouched behind her. "From the Tower. Look, they've got the bands!"

More faces emerged then, cautious as foxes. Four children in total, the tallest a boy who might have been thirteen, his arm wrapped in a filthy strip of cloth. They approached slowly, as if we were rabid creatures.

"Careful, Sam," said the boy with the bad arm. "Might be diseased."

"They're not diseased, they're Tower ravens," the girl insisted. "My gran took me to see them once. She said if they ever left, that'd be the end of everything."

"Well," Stuart muttered to me, "she wasn't wrong, was she."

I stepped forward, as boldly as my clipped-wing waddle allowed, and gave the girl a small bow of my head. It was, I felt, the diplomatic thing to do. She let out a delighted, disbelieving laugh, the first laugh any of us had heard since the sky burned.

"He's clever," she said. "Look, he understood me."

"She," I wanted to correct her, but of course could only croak, which she took as agreement.

The boy with the bad arm looked less charmed and more calculating, like Elder Koh does when weather turned. "They can't fly," he observed, watching Edward attempt an ambitious hop over a brick and fail spectacularly. "Wings are clipped. That means someone was keeping them."

"So?"

"So they're not wild. They won't know how to survive out here any better than we do." He crouched down to my level, wincing at whatever pain lived in that wrapped arm. "But maybe that's alright. We don't know how to survive out here either."

It was Ruby, of all birds, who made the decision for us. She waddled straight up to the smallest child, a boy hardly old enough to have all his words yet, and settled herself against his shins with a total, trust. The boy giggled and buried his hands in her feathers.

"Well," said Elder Koh, watching this with his ancient, knowing eye, "it seems we have found our Keepers after all."

"They're children," I said. "They can't keep us. They can barely keep themselves."

"No," Koh agreed. "But perhaps we were never meant to be kept, Mercy. Perhaps we were only ever meant to keep each other."

Sam straightened, testing maturity in his young face. "There's a place we've been staying. Underground, mostly safe, mostly dry. You can come, if you want. Extra eyes are extra eyes, even bird eyes." He paused. "Especially bird eyes, actually. You can see things we can't from up high."

"Not at present," Stuart said dryly, kicking at his clipped wing.

But I understood the gist of what Sam meant, and something in me said yes. We were creatures built to watch over things. Perhaps it did not matter so very much whether the things we watched over wore crowns or simply small, dirty, frightened faces.

"Lead on, then," I told him, though he could not understand a word of it. He seemed to understand anyway.

The children reminded me of happier times. Young humans like them always used to come to the Tower to see us, to shout happily and point at us as we went about our days in the courtyard. Now, we followed these four children, just as starving and tired as us, through a broken street strewn with scattered market stalls.

The tall boy with the bad arm stayed in the back, never taking his eyes off the others. I recognized the attention and care he gave them, especially the girl, who he regarded with the same familial love I felt for Ruby. He was their Elder, of sorts. He felt responsible for the others.

Sam and the young boy walked together, with Ruby, Stuart, and Edward close behind them in a mob of black feathers on the white street.

The girl, for her part, leaned down to look at me. I cawed in surprise and hopped away, flaring out my useless wings. She shook her head and held out her hand.

"Don't worry," she said softly, "I won't hurt you. I'm Cynthia."

I cocked my head and hopped back toward her. She was only a child, a small human with grease and dirt streaked across her skin. Curiously, I pecked at her hand.

She laughed. "My gran said ravens are the smartest birds. She had this saying..." The girl paused, thinking. "Pity the raven, too clever for its station in life. If you see one, do it a kindness and say something stimulating for it to think about." She tripped over the word stimulating.

I couldn't understand her words, but I saw meaning in them nevertheless. I did not miss the way her hands trembled, the shape of her shoulders all drawn in on themselves like our folded wings. I smelled the invisible layer of sweat mixed with sharp fear-bile. Instinctively I squeezed my flight feathers closer to my body, feeling my own anxieties pressing against the delicate bones of my ribcage.

"So," she finished, tremors rising into a crescendo all over her face and hands, "if you're so smart, how are we going to survive here?"

I didn't understand the question, but I understood the answer. She needed to be comforted. I thought of how Ruby trusted the small boy and wondered if perhaps I might be able to trust Cynthia the same way.

I rubbed my head against her outstretched arm and opened my beak to sing, approximating the sounds the Keepers made as they cleaned and decorated the Tower. "Fa... la... la, la, la." Then I stepped back and glared smugly at her, proud of my song.

She looked at me in disbelief for a moment, then a wide grin spread across her grubby face. "Sam!" she shouted. "Sam, did you hear that? They can sing!"

"They can sing!" I shrieked, pleased to hear her making a happy noise. "Sam!"

"Showoff," Ruby croaked back, but I didn't care. Edward took up the chorus, copying my exclamation, and Stuart followed his lead a moment later. The children looked at all of us in turn, amazed.

"That's all well and good," said the tallest boy, "but we've really got to get back home before dark falls. I don't want to be out here when we can't see a bloody thing."

The smallest boy sniffed as though he were sick. "Stop calling it home, Mateo! The tunnel isn't our home."

"Yeah, well, it's the closest thing we've got for now."

The children became quiet after that, and so did we ravens, sensing the gravity of the situation. Cullinan, always quiet and always watching, drew back to walk with Mateo. They both seemed to come to an accord, a satisfaction born of simple coexistence.

At last we came to the home of the children. It was a concrete cavern in the earth hidden between buildings, down a long staircase which proved difficult to navigate in our ambulatory state. When we reached the street below (for indeed, it did seem to be a street under the ground), we saw this was no ordinary cave. Bright hues and patterns covered every bit of the floor, walls, and ceiling, too deliberate to be natural. I saw shapes of humans, metal things, and beasts that could not possibly exist on Earth. Human hands had created this--for what purpose, we could not know, but it served to remind us of colour somewhere in this drab world.

"It's so beautiful, Mercy," squawked Ruby, looking up at the silhouette of a metal two-wheel high above us.

"It's not our Tower," I answered, looking at the dust and shattered glass on the floor. "There's nowhere to perch."

"Perches," said Elder Koh with a croak of amusement, "are a matter of perspective. We are once more with humans, fulfilling the ancient purpose our ancestors were given long seasons ago. Let us be grateful for what we have here, now."

I could not argue with that. Though the curb proved a difficult perch nevertheless.