It was like the Moon, yes — the same undulating surface, heavily eroded, crater on crater, so the surface was like a sea of dusty waves. But if anything the erosion was more complete here. There were hills — she was close to the rim wall of crater Bernini — but they were stoop-shouldered, coated in regolith. The smaller craters were little more than shadows of themselves, palimpsests, their features worn away.
She hadn’t met Dorothy since they had been with Malenfant on the Gaijin’s home world and the three of them had set off to return to the Solar System by their different routes. Dorothy seemed different to Madeleine: more closed-in, secretive, perhaps obsessive. Somehow older.
Dorothy paused and pointed to a hole in the ground. “Here’s where I live. Subsurface shelter. It isn’t so bad. Not if you’ve already spent subjective years in spacecraft hab modules.”
At Madeleine’s feet was a flattened boulder, its exposed top worn smooth, like a lens. She bent stiffly, scuffed at the soil, and prised the rock out of the dirt. Most of the rock had been hidden in the dirt, like an iceberg. Underneath, it was sharp, a jagged boulder.
“It probably dropped here a billion years ago,” Dorothy said, “thrown halfway around the planet by some impact. And since then any bits of it that stuck out have just been eroded flat, right here where it landed, layer by layer.”
Madeleine frowned. “Micrometeorite impacts?”
“Not primarily. At noon it gets hot enough to melt lead. And in the night, which lasts nearly six months, it’s cold enough to liquefy oxygen.”
“Thermal stress, then.”
“Yes. Shaped the landscape. Bane of the engineer’s life, here on this hot little world. Come on. Let me show you what I do for a living.”
They walked briskly through a shallow crater littered with bits of glass.
That, anyhow, was how it seemed to Madeleine at first glance. She was surrounded by delicate glass leaves that rested against the regolith, spiky needles protruding. There was, too, another type of structure: short, stubby cylinders, pointing at the sky, projecting in all directions, like miniature cannon muzzles. It was like a sculpture park.
Dorothy stalked on without pausing. Some of the petal-shaped glass plates were crushed under Dorothy’s careless feet; Madeleine walked more carefully. “We can just grow sail panels right out of the rock,” Dorothy said. “These things are gen-enged descendants of vacuum flowers from the Moon. I’ve made myself something of an expert at this technology. Good to have a profession, on a world where you have to pay for the air you breathe, don’t you think?” She tilted back her head, her face obscured. “Next time you see a solar sailing ship, think of this place, how those gauzy ships are born, morphing right out of the rocks at your feet. Beautiful, isn’t it?”
They walked on. Madeleine asked about Malenfant.
Dorothy shrugged. “I got back twenty years before you did. If he came directly back to the system after we parted, as he said he would, he might have arrived here centuries earlier yet. I don’t know what’s become of him.”
Madeleine studied her. “You’re troubled. The time we had on the Cannonball—”
“Not troubled, exactly. Guilty, perhaps.” She laughed. “Guilt: the Catholic church’s first patent.”
“And that’s why you work so hard here.”
“Analysis now, Madeleine?” Dorothy asked dryly. “I also work to live, as must we all… But still, yes, I failed Malenfant, there on the Cannonball. I used to be a priest. If ever there was a soul in torment, in his own silent, lonely way, it was Reid Malenfant. And I couldn’t find a way to help him.”
Madeleine scowled, irritated. “What happened on the Cannonball was about Malenfant, Dorothy, not about you and your guilt. Malenfant was a victim. A tool of the Gaijin, dragged across the Galaxy, part of plans we still know nothing about. Why should he put up with that?”
“Because he knew, or suspected, that it was the right thing to do, if the Gaijin had any hope—” She waved a gloved hand at the damaged sky. “ — of changing this. The rapacious colonization waves, the wars, the trashing of worlds, the extinctions. If there was even a chance of making a difference, it might have been right for Malenfant to sacrifice himself.”
“But he’s just a man, a human. Why should he give himself up? Would you?”
Dorothy sighed. “I’m not the right person to ask anymore. Would you?”
“I don’t know.” Madeleine was chilled. “Poor Malenfant.”
“Wherever he is, whatever becomes of him, I hope he isn’t alone. Even Christ had the comfort of His family, at the foot of the cross. You brought refugees here, didn’t you?”
Madeleine grunted. “I’m told that everybody here is a refugee. But here we are as safe as anywhere.”
Dorothy barked laughter. “You don’t get it yet, do you? Obviously you haven’t spoken to Nemoto… She’s still alive. Did you know that? Centuries old… Of all the places to come — this, Mercury, as the last refuge of mankind? Wrong. ”
“Mercury is deep in the inner system. So close to the Sun the Gaijin don’t want to come here.”
“But the Gaijin are not the enemy,” Dorothy hissed. “You have to think things through, Madeleine. We think we know how the Crackers work. They manipulate the target star, causing it to nova…” A nova: a stellar explosion, releasing as much energy in a few days as a star would have expended in ten thousand years. “The Crackers feed on the light pulse, you see,” Dorothy said. “They ride their solar-sail craft out to more stars, scattering like seeds from a burst fungus, sailing past planets scorched and ruined. We used to think novae were natural, a question of a glitch in a star’s fusion processes, perhaps caused by an infall of material from a binary companion. Now we wonder if any nova we have observed historically has been natural. Perhaps all of them, all over the sky, have been the responsibility of the Crackers — or foul species like them.”
And Madeleine started to see it. “How do you make a star nova?”
“Simple. In principle. You set a chain of powerful particle accelerators in orbit around your target star. They create currents of charged particles, which set up a powerful magnetic field, caging the star — which can then be manipulated.”
“…Ah. But you need a resource base to manufacture those thousands, millions of machines. And a place to make your new generation of solar sailing boats.”
“Yes. Madeleine, here in the Solar System, what would be the ideal location for such a mine?”
A rocky world orbiting conveniently close to the central star itself. A big fat core of iron and nickel just begging to be dug out and broken up and exploited, without even an awkward rocky shell to cut through…
“Mercury,” Madeleine whispered. “What do we do? Do we have to evacuate?”
“Where to?” Dorothy said, comparatively gently. “Meacher, remember where you are. We’ve already lost the Solar System. This is the last bolthole. All we can do is dig deep, deep down, as deep as possible.”
Something about her emphasis on those words made Madeleine look hard at Dorothy, but her face remained obscured.
“What are you doing here, Dorothy? You’re planning something, aren’t you?” Her mind raced. “Some way of striking back at the Crackers — is that what this is about? Are you working with Nemoto?”
But Dorothy evaded the question. “What can we do? The Crackers have already driven off the Gaijin, a species much older and wiser and more powerful than us. We’re just vermin infesting a piece of prime real estate.”