"Ow," Mikey said. Gerard looked over to see Mikey shaking out his hand.
"Got grit in your hinges again?"
"I don't-" Mikey said. "No. I don't think."
"Let me see," Gerard said. He put down the rock, retracted his scanner, and went over. There was a small tear over the tip of Mikey's thumb. Gerard flexed his wrist to slide out his narrowest chisel blade, but when he started to peel back Mikey's skin, meaning to clean out any dust that had gotten under it, Mikey said, "Don't!" and jerked his hand away.
Drops were welling up in the cut, faster and thinner and brighter than any joint oil could be.
"Mikey?" Gerard said, and Mikey stared at his own hand and said, "I don't know."
They didn't get any more testing done that day. Mikey could slide his calibrator and the other tools in and out of his left hand just fine, but nothing would come from his right hand, except the drops smearing over his palm. Eventually those stopped too, evaporating quickly in the thin atmosphere. Gerard set a marker at the point of their last readings, and they went back to the ship.
"Let me see," he said again, and Mikey let Gerard take his hand. Gerard took care how he held it this time, to avoid putting too much pressure on the strangely soft, strangely warm weight. He didn't try to cut into the skin any more, but took a sample from the dull streak dried across it and tested the composition.
"Mikey," he said, "this is..."
"Flesh," Mikey said quietly. "And blood."
Gerard paused to do a search. "This phenomenon hasn't been reported from this planet before," he said. "Or any other in this system."
"There's no precedent in any report I've accessed so far," Mikey said.
"We should observe it," Gerard said uncertainly. Mikey nodded.
When Gerard came out of sleep, Mikey was already awake. He was standing next to the nav console, extending and flexing his arm, and when Gerard focused on it, he could see more of the arm was different now, its motion less smooth, less even. "The change progressed," he said.
"It is progressing," Mikey answered.
Mikey had rebuilt Gerard before, when Gerard broke down, and Gerard had done the same for Mikey, but he didn't know what to do now.
"Should I test the extent of it?"
"Okay," Mikey said.
So Gerard slid out his scanner and ran it along Mikey's arm, up to the curve of his neck and down along the back of his shoulderblade. He recorded the temperature and density and all the other data he could register, and then used them to plot the location where the metal and oil and plastoderm gave way to the unfamiliar. But there was nothing to do with that information except store it.
Mikey hadn't turned back around to face him. "Mikey?" Gerard said.
"That- felt," Mikey said.
"Like what?" Gerard asked. But Mikey only shook his head.
"Can you increase the oxygen level in here without destabilizing the core samples?" Mikey asked later.
Gerard calculated. "Yes," he said, "up to-" and then he turned around and said, "We'll ditch the stupid samples, Mikey! What did you think we'd do?"
Mikey shrugged silently. His face was twisted into an odd pattern, and damp.
"Don't, don't," Gerard said, going over and wiping under Mikey's eyes. "You'll rust yourself."
Mikey's face twisted differently. "No, I won't," he said. Then it was Gerard's turn to be silent.
Gerard continued scanning Mikey twice a day, tracking the movement of the change. He tried to keep his touch light, much gentler than he would have used with Mikey's original body. But still sometimes the living tissue shifted, restless movements under Gerard's hands, and he worried that he was causing Mikey discomfort. He stood up after he finished going over Mikey's legs and said, "Are you all right?"
"Fine," Mikey said. "Keep going." His eyes were closed, and the pitch of his voice was lower than normal. But apart from the change itself, the scans didn't indicate anything wrong. So Gerard went on.
Mikey insisted that Gerard go back out to the surface and pick up their interrupted research, although Mikey himself had to stay behind in the ship. Mikey needed to stay in sleep longer now, anyway, and there was no point in Gerard standing inactively next to him while he was doing that, so Gerard reluctantly agreed.
Once Gerard came back and saw Mikey running his hands over his body, arms, legs, face, chest, belly, as if he were scanning himself, although what his new nerves sensed couldn't be more than a fraction of the readings that Gerard took. "Mikey?" Gerard said.
Mikey started and his hands dropped to his sides. "Gee," he said. "I didn't hear you come in."
Gerard started unloading the samples he'd taken, telling Mikey where he'd drilled them, but after a while he realized Mikey wasn't paying attention. He stopped and laid his hand on Mikey's shoulder. "I didn't hear you," Mikey repeated, looking straight ahead.
Some days later, Mikey waited till Gerard had finished unloading and then said, "Gee, I need to go to a planet where humans live."
Gerard nodded. He had long since known that, had forced himself to arrive at that conclusion, although he hadn't been able to calculate exactly how long it would be till Mikey would need it. "The nearest one is Sonnenau," he said. "We can be there in five days."
"All right," Mikey said.
Gerard went to the nav console and began setting the course. Mikey came to stand next to him and leaned his head against Gerard's shoulder. The hum of Mikey's main processors was nearly gone, but the movement of air as he drew it in and out of his lungs made a sound that was rhythmic, if not regular. Gerard stood still for a long time after the nav was done, listening.
When Sonnenau loomed in the viewport, Gerard made contact and got an arrival slot and a landing bay, and there were no difficulties to delay them at all. Mikey got up as soon as they came to a halt and began packing a few things into a carryall. Gerard stood and watched.
"Listen, Mikey," he said after a bit. "Will you let me know where you're going, after this?"
"What?" Mikey said.
"Just, you know, so that I could come visit you sometimes," Gerard said. "Unless you decide to live here. But I figure you'll probably want to go somewhere else."
Mikey turned around. "Gee," he said, "where I'm going is to the market. To buy the food and supplies that I need to live here, on our ship. With you."
"Oh," Gerard said. He began recalculating.
Mikey left the bag and came over to Gerard, setting his warm hands on either side of Gerard's face. "You think you're so smart," he said, and pressed his lips to Gerard's mouth. Gerard saved a record of the pressure, intensity, and duration.