“I want Mommy,” Mei said, and made the same impatient grunt that Daddy would.

“Well, you just wait right here, and I’ll see what I can do about that,” Doctor Strickland said with a smile. “Umea?”

“I think we’re good to go. Check with ops, load up, and let’s release it.”

“I’ll go let them know. You stay here.”

The woman nodded, and Doctor Strickland walked back out the door. The woman looked down at her, the pretty face not smiling at all. Mei didn’t like her.

“I want my painting,” Mei said. “That’s not for you. That’s for Mommy.”

The woman looked at the painting in her hand as if she’d forgotten it was there. She unrolled it.

“It’s Mommy’s space monster,” Mei said. This time, the woman smiled. She held out the painting, and Mei snatched it away. She made some wrinkles in the paper when she did, but she didn’t care. She crossed her arms again and scowled and grunted.

“You like space monsters, kid?” the woman asked.

“I want my mommy.”

The woman stepped close. She smelled like fake flowers and her fingers were skinny. She lifted Mei down to the floor.

“C’mon, kid,” she said. “I’ll show you something.”

The woman walked away and for a moment Mei hesitated. She didn’t like the woman, but she liked being alone even less. She followed. The woman walked down a short hallway, punched a key-code into a big metal door, like an old-fashioned airlock, and walked through when the door swung open. Mei followed her. The new room was cold. Mei didn’t like it. There wasn’t an examination table here, just a big glass box like they kept fish in at the aquarium, only it was dry inside, and the thing sitting there wasn’t a fish. The woman motioned Mei closer and, when Mei came near, knocked sharply on the glass.

The thing inside looked up at the sound. It was a man, but he was naked and his skin didn’t look like skin. His eyes glowed blue like there was a fire in his head. And something was wrong with his hands.

He reached toward the glass, and Mei started screaming.

Snoopy’s out again,” Private Hillman said. “I think his CO must be pissed at him.”

Gunnery Sergeant Roberta Draper of the Martian Marine Corps upped the magnification on her armor’s heads-up display and looked in the direction Hillman was pointing. Twenty-five hundred meters away, a squad of four United Nations Marines were tromping around their outpost, backlit by the giant greenhouse dome they were guarding. A greenhouse dome identical in nearly all respects to the dome her own squad was currently guarding.

One of the four UN Marines had black smudges on the sides of his helmet that looked like beagle ears.

“Yep, that’s Snoopy,” Bobbie said. “Been on every patrol detail so far today. Wonder what he did.”

Guard duty around the greenhouses on Ganymede meant doing what you could to keep your mind occupied. Including speculating on the lives of the Marines on the other side.

The other side. Eighteen months before, there hadn’t been sides. The inner planets had all been one big, happy, slightly dysfunctional family. Then Eros, and now the two superpowers were dividing up the solar system between them, and the one moon neither side was willing to give up was Ganymede, breadbasket of the Jovian system.

As the only moon with any magnetosphere, it was the only place where dome-grown crops stood a chance in Jupiter’s harsh radiation belt, and even then the domes and habitats still had to be shielded to protect civilians from the eight rems a day burning off Jupiter and onto the moon’s surface.

Bobbie’s armor had been designed to let a soldier walk through a nuclear bomb crater minutes after the blast. It also worked well at keeping Jupiter from frying Martian Marines.

Behind the Earth soldiers on patrol, their dome glowed in a shaft of weak sunlight captured by enormous orbital mirrors. Even with the mirrors, most terrestrial plants would have died, starved of sunlight. Only the heavily modified versions the Ganymede scientists cranked out could hope to survive in the trickle of light the mirrors fed them.

“Be sunset soon,” Bobbie said, still watching the Earth Marines outside their little guard hut, knowing they were watching her too. In addition to Snoopy, she spotted the one they called Stumpy because he or she couldn’t be much over a meter and a quarter tall. She wondered what their nickname for her was. Maybe Big Red. Her armor still had the Martian surface camouflage on it. She hadn’t been on Ganymede long enough to get it resurfaced with mottled gray and white.

One by one over the course of five minutes, the orbital mirrors winked out as Ganymede passed behind Jupiter for a few hours. The glow from the greenhouse behind her changed to actinic blue as the artificial lights came on. While the overall light level didn’t go down much, the shadows shifted in strange and subtle ways. Above, the sun-not even a disk from here as much as the brightest star-flashed as it passed behind Jupiter’s limb, and for a moment the planet’s faint ring system was visible.

“They’re going back in,” Corporal Travis said. “Snoop’s bringing up the rear. Poor guy. Can we bail too?”

Bobbie looked around at the featureless dirty ice of Ganymede. Even in her high-tech armor she could feel the moon’s chill.

“Nope.”

Her squad grumbled but fell in line as she led them on a slow low-gravity shuffle around the dome. In addition to Hillman and Travis, she had a green private named Gourab on this particular patrol. And even though he’d been in the Marines all of about a minute and a half, he grumbled just as loud as the other two in his Mariner Valley drawl.

She couldn’t blame them. It was make-work. Something for the Martian soldiers on Ganymede to do to keep them busy. If Earth decided it needed Ganymede all to itself, four grunts walking around the greenhouse dome wouldn’t stop them. With dozens of Earth and Mars warships in a tense standoff in orbit, if hostilities broke out the ground pounders would probably find out only when the surface bombardment began.

To her left, the dome rose to almost half a kilometer: triangular glass panels separated by gleaming copper-colored struts that turned the entire structure into a massive Faraday cage. Bobbie had never been inside one of the greenhouse domes. She’d been sent out from Mars as part of a surge in troops to the outer planets and had been walking patrols on the surface almost since day one. Ganymede to her was a spaceport, a small Marine base, and the even smaller guard outpost she currently called home.

As they shuffled around the dome, Bobbie watched the unremarkable landscape. Ganymede didn’t change much without a catastrophic event. The surface was mostly silicate rock and water ice a few degrees warmer than space. The atmosphere was oxygen so thin it could pass as an industrial vacuum. Ganymede didn’t erode or weather. It changed when rocks fell on it from space, or when warm water from the liquid core forced itself onto the surface and created short-lived lakes. Neither thing happened all that often. At home on Mars, wind and dust changed the landscape hourly. Here, she was walking through the footsteps of the day before and the day before and the day before. And if she never came back, those footprints would outlive her. Privately, she thought it was sort of creepy.

A rhythmic squeaking started to cut through the normally smooth hiss and thump sounds her powered armor made. She usually kept the suit’s HUD minimized. It got so crowded with information that a marine knew everything except what was actually in front of her. Now she pulled it up, using blinks and eye movements to page over to the suit diagnostic screen. A yellow telltale warned her that the suit’s left knee actuator was low on hydraulic fluid. Must be a leak somewhere, but a slow one, because the suit couldn’t find it.