She struggled upward, flowers exploding as they were touched by her boots. At the top of the rise, the flowers gave way to sulfur hardpan again. Looking back, she could see the path she had crunched through the flowers begin to erase itself.

For a long moment she stood still, venting heat. Crystals shattered soundlessly about her in a slowly expanding circle.

She was itching something awful now. Time to freshen up. Six quick taps brought up a message on her visor: Warning: Continued use of this drug at current levels can result in paranoia, psychosis, hallucinations, misperceptions, and hypomania, as well as impaired judgment.

Fuck that noise. Martha dealt herself another hit.

It took a few seconds. Then–whoops. She was feeling light and full of energy again. Best check the airpack reading. Man, that didn't look good. She had to giggle.

Which was downright scary.

Nothing could have sobered her up faster than that high little druggie laugh. It terrified her. Her life depended on her ability to maintain. She had to keep taking meth to keep going, but she also had to keep going under the drug. She couldn't let it start calling the shots. Focus. Time to switch over to the last airpack.

Burton's airpack. "I've got eight hours of oxygen left. I've got twelve miles yet to go. It can be done," she said grimly. "I'm going to do it now."

If only her skin weren't itching. If only her head weren't crawling. If only her brain weren't busily expanding in all directions.

Trudge, drag, trudge, drag. All through the night. The trouble with repetitive labor was that it gave you time to think. Time to think when you were speeding also meant time to think about the quality of your own thought.

You didn't dream in real-time, she'd been told. You get it all in one flash, just as you're about to wake up, and in that instant extrapolate a complex dream all in one whole. It feels as if you've been dreaming for hours. But you've only had one split second of intense nonreality.

Maybe that's what's happening here.

She had a job to do. She had to keep a clear head. It was important that she get back to the lander. People had to know. They weren't alone anymore. Damnit, she'd just made the biggest discovery since fire!

Either that, or she was so crazy she was hallucinating that Io was a gigantic alien machine. So crazy she'd lost herself within the convolutions of her own brain.

Which was another terrifying thing she wished she hadn't thought of. She'd been a loner as a child. Never made friends easily. Never had or been a best friend to anybody. Had spent half her girlhood buried in books. Solipsism terrified her–she'd lived right on the edge of it for too long. So it was vitally important that she determine whether the voice of Io had an objective, external reality. Or not.

Well, how could she test it?

Sulfur was triboelectric, Io had said. Implying that it was in some way an electrical phenomenon. If so, then it ought to be physically demonstrable.

Martha directed her helmet to show her the electrical charges within the sulfur plains. Crank it up to the max.

The land before her flickered once, then lit up in fairyland colors. Light! Pale oceans of light overlaying light, shifting between pastels, from faded rose to boreal blue, multilayered, labyrinthine, and all pulsing gently within the heart of the sulfur rock. It looked like thought made visual. It looked like something straight out of DisneyVirtual, and not one of the nature channels either–definitely DV-3.

"Damn," she muttered. Right under her nose. She'd had no idea.

Glowing lines veined the warping wings of subterranean electromagnetic forces.

Almost like circuit wires. They crisscrossed the plains in all directions, combining and then converging–not upon her, but in a nexus at the sled. Burton's corpse was lit up like neon. Her head, packed in sulfur dioxide snow, strobed and stuttered with light so rapidly that it shone like the sun.

Sulfur was triboelectric. Which meant that it built up a charge when rubbed.

She'd been dragging Burton's sledge over the sulfur surface of Io for how many hours? You could build up a hell of a charge that way.

So, okay. There was a physical mechanism for what she was seeing. Assuming that Io really was a machine, a triboelectric alien device the size of Earth's moon, built eons ago for who knows what purpose by who knows what godlike monstrosities, then, yes, it might be able to communicate with her. A lot could be done with electricity.

Lesser, smaller, and dimmer "circuitry" reached for Martha as well. She looked down at her feet. When she lifted one from the surface, the contact was broken, and the lines of force collapsed. Other lines were born when she put her foot down again. Whatever slight contact might be made was being constantly broken.

Whereas Burton's sledge was in constant contact with the sulfur surface of Io.

That hole in Burton's skull would be a highway straight into her brain. And she'd packed it in solid SO2 as well. Conductive and supercooled. She'd made things easy for Io.

She shifted back to augmented real-color. The DV-3 SFX faded away.

Accepting as a tentative hypothesis that the voice was a real rather than a psychological phenomenon. That Io was able to communicate with her. That it was a machine. That it had been built ...

Who, then, had built it?

Click.

"Io? Are you listening?"

"Calm on the listening ear of night. Come Heaven's melodious strains. Edmund Hamilton Sears."

"Yeah, wonderful, great. Listen, there's something I'd kinda like to know–who built you?"

"You. Did."

Slyly, Martha said, "So I'm your creator, right?"

"Yes."

"What do I look like when I'm at home?"

"Whatever. You wish. To."

"Do I breathe oxygen? Methane? Do I have antennae? Tentacles? Wings? How many legs do I have? How many eyes? How many heads?"

"If. You wish. As many as. You wish."

"How many of me are there?"

"One." A pause. "Now."

"I was here before, right? People like me. Mobile intelligent life forms. And I left.

How long have I been gone?"

Silence. "How long–" she began again.

"Long time. Lonely. So very. Long time."

Trudge, drag. Trudge, drag. Trudge, drag. How many centuries had she been walking? Felt like a lot. It was night again. Her arms felt like they were going to fall out of their sockets.

Really, she ought to leave Burton behind. She'd never said anything to make Martha think she cared one way or the other where her body wound up. Probably would've thought a burial on Io was pretty damn nifty. But Martha wasn't doing this for her. She was doing it for herself. To prove that she wasn't entirely selfish.

That she did too have feelings for others. That she was motivated by more than just the desire for fame and glory.

Which, of course, was a sign of selfishness in itself. The desire to be known as selfless. It was hopeless. You could nail yourself to a fucking cross, and it would still be proof of your innate selfishness.

"You still there, Io?"

Click.

"Am. Listening."

"Tell me about this fine control of yours. How much do you have? Can you bring me to the lander faster than I'm going now? Can you bring the lander to me? Can you return me to the orbiter? Can you provide me with more oxygen?"

"Dead egg, I lie. Whole. On a whole world I cannot touch. Plath."

"You're not much use, then, are you?"

There was no answer. Not that she had expected one. Or needed it, either. She checked the topos and found herself another eighth-mile closer to the lander. She could even see it now under her helmet photomultipliers, a dim glint upon the horizon. Wonderful things, photomultipliers. The sun here provided about as much light as a full moon did back on Earth. Jupiter by itself provided even less.