Amos rose from behind one of the boxes nearest the wall. His Martian armor had a long pale streak across the chest and two white circles just below the ribs. Amos limped toward him.

“Sorry, Doc,” he said. “Givin’ it to you was my bad call. Maybe next time, right?”

Prax looked at the big man’s open hand, then carefully put the gun in it.

“Wendell?” Holden said. Prax still wasn’t sure where he was, but he sounded closer. That was probably just Prax’s hearing coming back. The acrid smell in the air changed to something more coppery. It made him think of compost heaps gone sour: warm and organic and unsettling.

“One down,” Wendell said.

“We’ll get a medic,” Holden said.

“Nice thought, but no point,” Wendell said. “Finish the mission. We got most of them, but two or three made it through the door. They’ll raise an alarm.”

One of the Pinkwater soldiers stood up. Blood was running down his left arm. Another lay on the floor, half of his head simply gone. Holden appeared. He was massaging his right elbow, and the armor showed a new scar at his left temple.

“What happened?” Prax asked.

“You started a gunfight,” Holden said. “Okay, let’s move ahead before they can set up defenses.”

Prax started noticing other bodies. Men and women who had been eating pizza and listening to music. They’d had pistols, but Holden’s people carried automatic shotguns and assault rifles and some had military-looking armor. The difference in outcome hadn’t been subtle.

“Amos, take point,” Holden said, and the big man moved through the doorway and into the unknown. Prax moved to follow, and the head of the Pinkwater people took his elbow.

“Why don’t you stay with me, professor,” he said.

“Yes. I’ll … all right.”

On the other side of the door, the nature of the rooms changed. They were still clearly in the old tunnels of Ganymede. The walls still had their webwork of mineralized frost, the lighting was still old-fashioned LED housings, and the gray walls showed where ice had melted and refrozen during some climate system glitch years or decades before. But walking through that doorway was walking from the land of the dead into something living. The air was warmer, and it smelled of bodies and fresh soil and the subtle, sharp scent of phenol disinfectant. The wide hall they entered could have been the common room in any of a dozen labs where Prax had worked. Three metal office doors were closed along the far wall and a rolling metal freight gateway hung open ahead of them. Amos and Holden went to the three closed doors, Amos kicking each in turn. When the third flew open, Holden shouted something, but the words were lost in the bark of a pistol and Amos’ return shotgun fire.

The two remaining Pinkwater soldiers who weren’t Wendell scuttled forward, pressing their backs to the wall on either side of the freight gateway. Prax started toward them, but Wendell put a restraining hand on his shoulder. The man on the left side of the door ducked his head into the doorway and then out again. A bullet gouged a streak in the wall where it missed him.

“What can you give me?” Holden asked, and for a moment Prax thought he was talking to them. Holden’s eyes were hard, and the scowl seemed etched into his skin. Then Naomi said something to make him smile, and he only looked tired and sad. “All right. We’ve got a partial floor plan. Through there, we’ve got an open room. It drops down about two meters, with exits to our ten o’clock and one o’clock. It’s built like a pit, so if they’re setting up defense here, we’ve got the high ground.”

“Makes it a damned stupid place to set up a defense, then,” Wendell said.

Gunfire chattered, three small holes appearing in the metal of the freight gateway. The people on the other side were nervous.

“And yet the evidence suggests …” Holden said.

“You want to talk to ’em, Cap?” Amos said. “Or do we head straight for the obvious thing?”

The question meant something more than Prax understood; he could tell that much. Holden started to say something, hesitated, and then nodded toward the doorway.

“Let’s get this done,” he said.

Holden and Amos jogged toward the gateway, Prax and Wendell close behind. Someone was shouting orders in the room beyond. Prax made out the words payload and evac, his heart going tight. Evac. They couldn’t let anyone leave until they found Mei.

“I counted seven,” one of the Pinkwater soldiers said. “Could be more.”

“Any kids?” Amos asked.

“Didn’t see any.”

“We should probably look again,” Amos said, and leaned out the door. Prax caught his breath, expecting to see the man’s head dissolve in a rain of bullets, but Amos was already pulling back when the first shots started.

“What are we working with?” Holden asked.

“More’n seven,” Amos said. “They’re using this as a choke point, but the fella’s right. Either they don’t know what they’re doing, or there’s something in there they can’t pull back from.”

“So either panicking amateurs or something critical to defend,” Holden said.

A metal canister the size of a fist rolled through the gateway, clanking. Amos picked the grenade up casually and tossed it back through the doorway. The detonation lit the room, the report louder than anything Prax had ever heard before. The ringing in his ears redoubled.

“Could be both,” Amos shouted conversationally from very far away.

In the next room, something shattered. People were screaming. Prax imagined technicians like the ones from the previous room shredded by shrapnel from their own grenade. One of the Pinkwater soldiers leaned out, peering into the haze of smoke. An assault rifle blatted, and he pulled back, clutching his belly. Blood poured between his fingers. Wendell pushed past Prax, kneeling by his fallen soldier.

“Sorry, sir,” the Pinkwater man said. “Got careless. Leave me here and I’ll guard the rear as long as I can.”

“Captain Holden,” Wendell said. “If we’re going to do something, we’re better off doing it soon.”

The screaming in the other room got louder. Someone was roaring inhumanly. Prax wondered if they’d had livestock in there. The bellowing sounded almost like an injured bull. He had to fight the urge to put his hands over his ears. Something loud happened. Holden nodded.

“Amos. Soften them up, then let’s head in.”