In the eternity of star-ache where space coils around matter like a wounded animal, I hang in agony. Three supermassive black holes lurk in the corner of my hearing, each in a different corner of the galaxy cluster. Triangulation points. The calculation is redone every 4.5 microseconds, balm and torture both to my space-stretched mind. The ship’s computer tugs ceaselessly at my fragile gray matter, demanding that I chart its course.

So I listen. To star systems and gravitational waves I listen. With two ears and two eyes and two hundred and six bones I listen. I translate what I hear somewhere in the shadowed depths of my brain, the places that say I feel instead of I think, and as I translate, I sing. Without cease, the coordinate-song flows from my throat.

Entering sector 85613, the computer tells me. I receive a fetch request for an updated trajectory. I, whose eardrums pulsate in rhythm with the deaths of suns, pass back the trajectory parameters in a lightning instant. Already I’m trilling the sequence of chimes that the ship will use to build its map of nearby space. If my mouth were my own, I would sob. The computer asks me to confirm the projected coordinates for the incision that the engine is about to make in the fabric of the void, cutting apart space-time and folding it into a more pliant form. I confirm, a single note high and keening, the intensity of nova-tremor quaking my marrow. In choral unison, the ship’s computer and I schedule the incision time for 15:32:54 local. If my mouth were my own, I would scream.

A mouth, a wound. A melody, a spill of blood. Twelve years I’ve spent listening. Twelve years as an instrument made of skin and tendon and bone and brain, voice guiding this ship through the dark.

No—no, let’s be precise. Precision is the one luxury afforded to me, aided by the encroachment of the ship’s computer into my mind. If my mouth were my own, I could recite the number perfectly: eleven years, three hundred and sixty-four days, two hours, seventeen minutes.

I’ve made a decision. I will not spend twelve years as an instrument.

• • • •

If I try, I can recall what it was like before. Back when my body and I were allies rather than enemies, I was a stowaway. Stowaways know their bodies in ways that few people do. On hands and knees I crawled through vents to avoid well-traveled corridors, and so I knew my hands and knees as well as a lover’s. Arms curled around my ribcage, I slept in the narrow gaps between crates in cargo holds, and so I knew my ribcage as well as a moon knows its planet. And once—the day my presence was discovered—I stood before the captain, and in that moment my only friend was my spine, aching but still upright, and I knew it as well as anyone could ever know anything in this world.

Oh, if only I’d managed to disguise the fact that I was born in space, far away from the comforting grasp of a planet’s gravity well. I was scared. I wasn’t thinking straight. As I was dragged in front of the captain, I felt a tremor from the vacuum and shuddered, then hummed under my breath to ease the ache of it. The captain heard. Instantly he knew I’d been born with the void-quake in my ears.

His ship was an old freighter that creaked through the starry black, slower and slower with each journey, perpetually breaking down. He needed money. It was hard to get people to pay for freight transportation that went so slowly, aided only by a feeble computerized navigational program. He was losing business to competitors with sleek, expensive vessels staffed by human navigational singers. His ship could cut and fold the fabric of space as well as any other, but only a human singer could sense exactly the right places to make those incisions. The precision and efficiency of a singer’s work was unparalleled. Without one, a trip from one end of a galaxy cluster to the other was a journey of five months. With one, the journey was only five days.

The captain smiled so gently. He spoke so kindly. “Only for a little while,” he assured me. “Only until you’ve paid off your debt. For the cost of room and board.”

Ordinary singers are never hooked into the computer for longer than a week at a time. The mind grows strained after much longer than that. It grows difficult to hear anything but the distant gravity-sigh. It becomes hard to shape the tongue around anything but trilling coordinate-song.

That wasn’t a concern to the captain. He never intended to unhook me, not ever. That would be wasteful, costly. Dangerous, too; I could’ve made a break for it. He opened up my skull and introduced my gray matter to the ship’s computer, and from that day on the computer and I have never once been parted. I know it as a steely blue thing in my mind, cold and clear as chipped glass in wintry morning light. For nearly twelve years it’s processed my song and directed the engine accordingly. For nearly twelve years it’s been my sole companion as I lie here, suspended in the liquid darkness of the isolation chamber, reduced to aching melody.

I wonder. Does the captain comprehend the danger? Does he even suspect? Could he ever guess the true reason why it’s unwise to leave a singer singing for too long?

• • • •

A series of chilly commands trickle into my thoughts. A new destination: sector 24183. A stop on the way: sector 91728, a refueling hub. An injunction to begin calculating immediately.

The first step is always the same: the opening of the ears, like digging fingers into a wound. Building my body into a threshold, opening myself into agony.

The second step comes from without, not within. The nearby stars shiver the cosmos with their weight. I feel it in my teeth. I cast myself wider, like a net, and with the ache in my tendons I feel my three black holes, my triangulation points. With them I locate the desired destination, then locate myself, and then with a singer’s perfect immediacy I know the answer. I understand exactly where the engine might be brought to bear, bladelike, on the vacuum. With excruciating clarity I know how the universe will part itself around the ship, so long as the ship follows the path I set out for it.

Each step is a compulsion, inexorable, but the third step is the fiercest of all the compulsions. My every bone is a bell. The only thing left to do is to part my lips and ring. Refusal is unthinkable, literally—a singer’s mind is crowded with feverish translation, gravity-sigh bleeding into coordinate-song. Silence constitutes pain. Music constitutes release. Staying quiet would mean holding the void-quake within myself. It would mean shaking apart. This is why singing is a compulsion: denying it is death. There can be no more than a microsecond of hesitation between feeling space tremble and crying out a path through its dread contours.

A microsecond of hesitation isn’t enough time to think. It’s not enough time to guide the arc of the melody that spills from me. It’s only enough time to react. To exploit it—lever it open—unfold it into potential—such a thing would be utterly unreasonable. It would require every part of the desired exploit to proceed without being bogged down by conscious thought. Every contour of it would need to be instinctual. Every aspect would need to be ingrained deeper even than muscle memory.

To use that microsecond to interrupt the compulsion to translate—redirect the tremble, reshape the song—should be impossible. It would require a small eternity of practice, a personal infinity of atomic resistances conducted in the minute interval between threat and consequence.

In my case, that eternity equals eleven years, three hundred and sixty-four days, two hours, and seventeen minutes.

• • • •

I sing the captain a path through the emptiness between galaxies. It’s not the one he wants me to make. I wonder if he’ll notice the dissident discordance. It doesn’t matter if he does. There’ll be no time for him to halt the engine. The ship takes up my final crescendo at a speed too swift for human intervention. I chart the captain a direct route into a black hole grave.

The event horizon comes swift and gentle upon us. I alone hear its roar.

The ship, the captain, the song, the singer—together we fall. First the groan of the hull, then a death-rattle from deep in the guts of the ship. Then the sound of metal giving way, loud enough to shatter a world.

And then, at last, silence.