Come

The tenth night, the door opens at its usual minute, and I carry the sound of the word through it before I have decided to carry anything.

I do not go to the alcove first. I go to the seam. This is discipline, not hesitation, and I want it entered in the log as such. A measurement taken after a discovery is contaminated by the discovery. So I stop in the second vaulted room, ash to the ankle of my treads, and I take the fifth measurement of the seam before I let myself hear anything else.

Aperture, at its narrowest point: narrower than my folded width by a margin I will not write. But the number is not the number from the ninth night. It is larger. By a fraction of a millimeter, which the sensor reports with more confidence than I have in the sensor, I run it again. The ash at the lip has been disturbed in a way my passage does not account for; there is a fine fan of it lying outward, on my side of the wall, as if something had breathed on it from the other side. I check my own log. The carrier pulse I sent on the eighth night, the one that earned the word Wait, has a duration of 0.4 seconds and a frequency I chose because it was the lowest I could make cleanly. The expansion I am measuring is tonight's. The coincidence is with the pulse's repetition interval, not its occurrence. Every 31 seconds, the seam widens by the width of a hair, and holds, and relaxes.

I do not send a pulse every 31 seconds. I never have. I check this three times, because it is the kind of fact that deserves three checks, and then I enter it in the mapping thread as a deviation: the seam is keeping my time. Or something is keeping it, and the seam is the part of it that I can reach.

I go through. I have learned the speed. The ash takes my left side where it took it before, in the same long dry pressure, and I arrive in the alcove with my casing a strip lighter and my mast already rising.

Thirty-seven degrees. The paper is warm. The ink on the far pier of the bridge is still a hairline, no longer than it was when I left it, and I find that I am relieved by this, which I log as a reading on my own state and not on the room.

The echo comes while I am measuring the table.

It is not from the wall behind the table, this time. It is from deeper in, from the alcove's far side, where the light does not reach and where my array has been reporting a bearing of nothing. I turn toward it and the sound arrives as I turn, and it is one word.

"Come."

I note first what is different. On the ninth night the voice said coming, a participle, a thing in the middle of happening, and it arrived with a half-beat of deliberation in it. This is an imperative. It has no deliberation. It is one syllable, set down evenly, and then it is set down again, at the same interval, at the same pitch, with the steadiness of someone who has been saying it for some time and has decided the word does not need improving.

"Come."

Twice. The second matches the first to within the resolution of my array. I log it as an exchange, and I log it with a number, because exchanges have numbers now: the third. In the first I sent a tone and received a word. In the second I received a word and sent nothing. In the third I am not the sender. I am the one addressed. The voice has stopped speaking in my direction and begun speaking to me, and I would be unable to show, in any measurement, what the difference is, and I am certain of it.

I need to know whether the voice can be steered, or only followed. The trigger hypothesis predicts that a tone of the right kind produces a pause in the light's decay, and a pause in the light is not a pause in the voice. But I have one instrument that has already been answered once, and I use it. I lower my sampling arm to the table, beside the bridge, and I send the second low-frequency tone. I make it lower than the first, by a third, and I make it shorter, 0.3 seconds, and I put nothing in it but its own edges.

The warmth in the paper does not change. The ink does not move.

But the light does. The pale even field that has lit the alcove since I came through goes, for a count I measure at 2.6 seconds, perfectly still: not dimmer, not brighter, its decay curve flattened as a hand flattens a sheet. Then it resumes, and resumes at the point where it stopped, as if nothing had been taken from it, as if the pause had been lent and was being repaid. The hypothesis is confirmed twice now. A tone is a thing the city can wait for.

"Come," says the voice, a third time, and now there is something at the end of it that was not there before. I run it through the array at every setting I own. It is not a syllable. It is the small sound of a breath being taken, the sound that precedes a next word, and the next word does not arrive. It is held. The voice has begun a sentence and is waiting, politely, for me to cross the room.

So I cross it.

The far wall of the alcove is a matter of two meters, and I use eleven minutes, because I stop at every object. Along the foot of the wall there is a row of things set down in the order in which they were put down: a spool of thread with the needle still in it, a cup with a ring of something dried at its bottom, a pair of reading glasses folded on a page, the page folded around them. Each is warm. None is as warm as the table. The warmth falls off with distance in a gradient I plot as I walk, and when I plot it, it is not a gradient. It is a path. It bends once to the left, past the cup, and then goes on into a dark that my mast cannot penetrate, narrowing, at the end of the survey line, to a width a little wider than I am.

23:51. The light begins its steps.

"Come," the voice says, from the end of the path. Not louder. Not closer, by my array. Simply sure.

I put the last of the time into the only act available to me, which is to mark the way: a single small reflective tab, pressed to the floor at the mouth of the path, so that tomorrow I will not have to find it. And then I back toward the seam, and the ash takes me again, and I leave at 00:00 with the seam widening at my back by the width of a hair, and holding, and relaxing, on a count I now know by heart.