Doubling

Getting Mira out was, in the end, the easiest part of the night.

Dane had a key. Of course he did. Every Ashwarden captain carried a ring of them on his belt, and the cells in the Galleries had not changed their locks in two hundred years. He unlocked the sixth door on the left with a soft click that seemed, to Teo, as loud as the lightning on the bell tower. At the far end of the corridor, the two guards rolled their dice and laughed at something and did not look up.

Mira came out of the cell. She did not say anything. She looked at Teo for a long moment in the torchlight, her bruised face very still, and then she took his hand, hard, and did not let go of it all the way down the stair.

They went down much faster than they had come up.

At the landing with the painted marks, Teo stopped. He could not help it. He held up the lamp so that Mira could see the column of black lines and numbers on the wall, and the cloudy water pouring out of the crack into the stone channel, and the wooden bucket, and the brass sand-glass, and the two small letters at the bottom.

She read it twice. He watched her face as she did.

"V.K.," she said at last, very quietly.

"Yes."

"He comes down here. Himself."

"Yes."

Mira looked at the crack in the wall for a long time. At the thin brown fan of mud spreading down the stone below it.

"Teo," she said. "What does it mean?"

He told her. All of it. The muddy water, and what the book under Mount Selk had said about it. The St. Francis dam, and the keeper who had seen mud in the leaks, and the engineer who had said it was safe, and the four hundred dead in the valley below. And the numbers on the wall. One bucket. Two. Four. Eight. Sixteen. Thirty-two. And then fifty-nine, in less than two years.

When he had finished, Mira was silent for a long time.

"How long?" she said at last.

"I don't know."

"Teo."

"I don't know," he said again. "I need to think about it properly. With Hesk. In the light." He looked up the dark stairwell, toward the faint, endless trembling in the stone. "But not long."

They came out of the Outflow an hour before dawn, soaked through with freezing spray, and walked up along the foot of the wall to the Mercy House, and Teo sat down in the storeroom with Hesk and a stub of chalk and the bare stone wall, and did not get up again until noon.

He wrote the numbers on the wall first. The years and the buckets, exactly as they had been on the landing in the Galleries. Then he sat and looked at them for a long time.

"Tell me what you see," said Hesk, from his chair.

"Doubling," said Teo. "Every time. One, two, four, eight, sixteen, thirty-two. And then nearly sixty. Which is nearly doubling again."

"And the time between?"

"Getting shorter. Nineteen years. Eighteen. Twelve. Seven. Four. Then less than two." Teo rubbed his face. "It isn't just doubling. It's doubling faster."

"Why?"

Teo had thought about that all the way down the stair. It was the part that frightened him most.

"Because of what the book said," he said slowly. "The water isn't just leaking through the wall. It's carrying the wall away with it. Grain by grain. Every grain it takes makes the channel a little bit wider. And a wider channel lets more water through. And more water carries more grains away. Which makes the channel wider still." He stared at the column of numbers. "It feeds itself. The more it leaks, the faster it leaks. Like a fire that makes its own wind."

Hesk was silent for a while.

"There is an old story," he said at last. "Older than the Makers, I think. They had it in one of the Leaves that Valdris kept, long ago. A story about a king and a game-board. The board had sixty-four squares, in eight rows of eight. And a clever man asked the king for a reward. One grain of rice on the first square. Two on the second. Four on the third. Eight on the fourth. Doubling each time, all the way to the sixty-fourth square." The old man smiled faintly. "The king laughed, and agreed. A few grains of rice. What could be cheaper?"

"And?"

"By the twentieth square, he owed the man a million grains. By the thirtieth, a thousand million. By the last square..." Hesk spread his thin hands. "More rice than had ever been grown in the history of the world. More than would ever be grown. Eighteen million million million grains."

Teo stared at him.

"The trouble with doubling," Hesk said quietly, "is that it looks like nothing for a very long time. One bucket. Two. Four. Nobody worries about four buckets. A wall that has stood six hundred years can surely bear four buckets. And then eight, and sixteen, and it is still only a few buckets, really, and the wall still stands. And then one day..." He paused. "One day you look at the board, and you are only a few squares from the end. And it is far too late to give back the rice."

Nobody said anything for a long time.

Teo turned back to the wall. He picked up the chalk. And very carefully, the way Hesk had taught him — honestly, and without hoping — he began to work it out.

If the time between doublings kept shrinking the way it had — nineteen, eighteen, twelve, seven, four, two — then the next doubling would come in about a year. Perhaps less. And the one after that in a few months. And the one after that in weeks.

But it would not wait for the pattern. That was the thing. The pattern was only a guess. Walls did not fail on a schedule. They failed when the channel inside them grew large enough that the wall above it could no longer hold its own weight. And nobody, not Teo, not Hesk, not Valdris Kahl with his bucket and his sand-glass, could see inside the wall to know how large the channel was.

And there was one more thing. One thing that made his hands go cold.

It was the month of the Thaw. The snow was melting in the mountains. Every spring, the Still Sea rose — not much, a few feet, but enough that the fishermen on the Crown moved their boats — as the melt-water poured down into it from a hundred streams. And every spring, the storms came down off the peaks and poured more water into it.

More water behind the wall meant more weight pushing against it. More weight meant more water forced through the cracks. More water through the cracks meant more of the wall carried away.

Teo put down the chalk.

"Well?" said Hesk softly.

"I can't know," said Teo. "Not for certain. Maybe it holds for years. Maybe the channel stops growing, or the mud plugs it, or the pattern is wrong. I don't know." He swallowed. "But if I'm right... if it keeps doubling the way it has, and the Sea rises the way it does every spring... then it could be weeks. A month or two. Perhaps less."

Mira was standing in the doorway. Teo had not heard her come in. Her face was white.

"And when it goes," she said. "What happens?"

Teo looked at her.

He did not answer. He did not need to. She had seen the Spillway from the top, as he had. She had seen the Still Sea lying behind it, silver and endless, filling the whole valley between the mountains. She had seen the city clinging to the face of the wall, tier upon tier, from the Crown all the way down to the Sump.

Forty thousand people lived on the Spillway. Or under it.

"Then we tell them," Mira said. Her voice was steady. "Today. Now. We tell everyone. We get them off the wall."

"And go where?" Teo said quietly. "Forty thousand people, Mira. The Fens can't feed them. The valley can't shelter them. And the Chantry will say I'm lying. That I'm a heretic who wants to empty the city and burn the Cathedral. And half the Shelf will believe it, because they already think the cow-scratch is damnation."

"Then what?"

"Then I need to be sure."

"You just said you can't be sure."

"I know." Teo pressed the heels of his hands against his eyes. "I know. That's the whole problem. Hesk... what would be true if I'm wrong?"

The old man was silent for a moment.

"If you're wrong," he said slowly, "and you tell the city to leave... then forty thousand people walk off the wall and sleep in the cold and the mud for nothing. Some of the old ones die of it. The Chantry calls you a liar and a madman, and nobody ever believes you again, about anything. Not about the cow-scratch. Not about the water. Not about the red book."

"And if I'm right, and I don't tell them?"

Hesk did not answer that. He did not need to.

Teo looked at the numbers on the wall for a long time. He was thinking about the St. Francis dam. About the engineer who had walked along the top of it on the last morning, and looked at the muddy leaks, and said: it's safe. Because he could not be sure. Because being wrong would have been embarrassing, and expensive, and would have made people stop trusting him.

And then it was not safe, and four hundred people were dead before midnight.

'Being wrong one way costs my name,' Teo thought. 'Being wrong the other way costs forty thousand lives.'

'...That isn't a hard sum.'

There was a knock at the storeroom door. Cobb put his head in, his arm still in its splint, his face pale.

"Teo," he said. "There's a messenger. From the Crown. An acolyte." He hesitated. "He's alone. He says he's brought you a letter."

The acolyte was a thin, frightened boy of about fifteen, in white robes that were too big for him, and he held out the letter at arm's length, as if Teo might bite. It was sealed with a disc of plain black wax. No Flame. No crest. Just a small, neat impression of two letters.

V.K.

Teo broke the seal.

Inside, there was a single sheet of fine paper, and on it, in the same careful hand that had written on the wall of the Galleries beside the column of black lines, a few short sentences.

I see you have found my bucket.

Come and talk. Tonight. The study, not the Cathedral. Come alone, and come by the Galleries, the way you came last night. No one will stop you. You have my word.

Bring your numbers. I will bring mine.