While Ender analyzed the half-exploded corpse of the alien rat-crab, Carlotta and Cincinnatus made repeated trips to the alien vessel in the Puppy. They did not return to the airlock. Instead, with Sergeant to protect her in case the ship started trying to defend itself and repel their tiny invasion, Carlotta opened all the maintenance hatches and took measurements and charted wiring and did whatever other engineering tasks were within her reach to figure out how the ship worked and, if possible, get some idea of what awaited them inside.

Both projects were getting fascinating results; Bean checked in on them every hour or so, and kept the audio channels on so that if they said anything, he could respond, just so they thought he was looking over their shoulders.

He wasn't, though. He had a project of his own. He was using the Herodotus's instruments and drones to probe the planet they were orbiting.

After two days of study, Ender had his report ready, and so did Carlotta and Sergeant. They gathered in the cargo hold for show and tell.

Ender began it.

"This is a Formic ship," he said. "The proteins in the rat-crab are the complete set of Formic-world proteins, with no extras.

"But here's the odd thing. The DNA is almost identical to the Formics' own genome as gathered and recorded from the many corpses after the war. There are key differences, but they're localized. It's as if the Formics went for a kind of perverse neoteny -- these rat-crabs seem to be a deliberate throwback to an earlier stage in Formic evolution, with these savage claws spliced on, and a hard carapace, which is only vestigial in the adult Formics."

Carlotta and Sergeant understood the implications at once. "So the Hive Queens can modify their own offspring," said Sergeant. "They decided that some of their babies would be those little monsters."

"I doubt they thought of them as their children anymore, if they ever did," said Carlotta. "When you have babies by the thousand, I bet the Hive Queens had no qualms about regarding a few of them as animals."

"There must be some limiting factor to their population," said Sergeant. "Or so the Hive Queen that created them intended. It might not have been the Hive Queen of this colony. They might have been developed long before this voyage and then reproduced naturally. The Formics might not even have remembered that these rat-crabs began as their kin."

"Do you think they're edible?" asked Carlotta. "Not to us, but ..."

"They're meaty," said Ender. "You're right, this might be dinner on the hoof."

"What kills them?" asked Sergeant.

"Anything. Their carapace doesn't protect them from anything stronger than the teeth of smaller animals. They could crush each other, and they could be mashed by a fist-sized rock. So you tell us what weapons we should use to keep them at bay."

Sergeant nodded. "No bullets, not on a ship. I wondered if we could slow them down with a sedative spray."

"I'd have to have a living specimen to see what worked on them," said Ender. "But there are sedatives that have been used on specimens of Formic-world fauna from several of the colony worlds. I could whip up a cocktail of seds that have no effect on humans."

"I just don't want to go in killing them wholesale," said Sergeant. "Now that we know they're Formic-derived, it's not impossible that they're actually the ones piloting the ship."

"Brain's too small," said Ender.

"But they might have queens," said Sergeant. "Or some kind of collective mind that's smarter than any individual. I just don't think we should go in killing. I keep thinking of the old vids of the Formics during the Scouring of China, that vile fog that reduced living creatures to pools and piles of protoplasmic goo."

"So let's have several sedatives ready that can be delivered as a fog," said Bean. "And a good solid backup plan. An acid spray, for instance. Even if they're sentient or semisentient, if they come at us to kill us, we hit them first and leave them dead."

"Carlotta?" he said. "What do we know about their ship?"

"It's definitely older tech. And it's Formic technology -- no writing, but some major color coding. Lots of little motors, which is why they need to have all these maintenance hatches. Of course they had to eliminate a lot of doorage in later ships when they got up to relativistic speeds. This design wouldn't do at all.

"I think they build the ship in space by attaching everything to an asteroid they sculpted into the shape we're seeing. Probably most of the metal in the ship's frame and hull came from the iron and nickel and such in the rest of the asteroid. But it's not the impermeable alloy they used in the ships that invaded Earth back in the 2100s."

"They didn't need it yet," said Sergeant. "At only ten percent lightspeed."

This ark showed that Formics sent out their colony ships with no defenses against attack, only a primitive collision shielding at the front. The Formics had turned out to be devastatingly formidable in war, but war was almost certainly not their intention when they came to Earth.

"Nice to know," said Bean. "Fortunately, the argument never mattered anyway. What else?"

"The huge pillars are structural -- the whole strength of the ship is vertical rising out of the rock, like a skyscraper. But they're also hollow. Rocket engines, and they carry fuel. Not radioactive, lots of carbon traces. It must be a very efficient fuel because even if the rock contains huge fuel reservoirs, it's not as if they can ever take this thing down to a planetary surface to process whatever carbon-based fuel source they use."

"They don't need much fuel," said Bean. "It's a generation ship, so they don't have to accelerate much. Very slow burn until they reach cruising speed, and then nothing until deceleration."

"No way to guess how much fuel they have left. This planet might be their last hope, or just a casual visit to see if it might do. The machinery I looked at was aging but it works fine."

"Aging like a thousand years?" asked Bean.

"No. More like a hundred years. I think everything's been replaced again and again during the voyage. Plenty of indications that there's been a lot of servicing over the years. But none recently."

"Good work, all of you," said Bean. "I know there's a lot more in your reports, and I've scanned your data as you collected it. I think we have all the useful information we're going to get from the outside, and from that lump of rab that Sergeant brought back."

"Rab," said Sergeant, giggling a little. "Rat-crab."

"Half a rabbit," said Carlotta.

"'Rab' it is," said Ender. "Until they tell us what they call themselves."

"Now, when you go inside," said Bean, "you have to remember that Formic-based life-forms probably all have some degree of mental communication. Even if it's just a sharing of impulses and desires and warnings, they can tell each other what they need to know. So if any of the rabs notices you, they all know you're there. They might be smart enough to set ambushes. You have to be alert. And if it gets dangerous, get out. You are not replaceable. Do you understand me?"

Sergeant nodded, Carlotta gulped, and Ender looked bored.

"Ender," said Bean, "it looks to me as if you think you're not going in with the others."

That woke him up. "Me?"

"Three," said Bean. "I'd go myself, but you know my limitations."

"But I'm the biology guy," said Ender.

"Precisely why you need to go," said Bean. "Three for defense is the minimum anyway, but if you're there, you can learn things on the spot instead of waiting for them to bring things back for you to study."

"But I'm -- I'm not trained for --"

Sergeant looked at him with contempt. "You think you're above getting your hands dirty."

"I was up to my elbows in rat-crab blood," said Ender.

"He didn't mean literally 'dirty,'" said Carlotta. "You think we're expendable and you're the irreplaceable one."

"Nobody's expendable," said Ender. "I just won't be much help."

"You beat me," said Sergeant dryly. "Don't pretend you're helpless."

"He's scared," said Bean. "That's all."

"I'm not a coward," said Ender coldly.

"We're all scared," said Carlotta.

"Terrified," said Sergeant. "When those rab bastards came at me I pooped my pressure suit. Nobody in his right mind isn't scared going into unknown territory facing fast-moving enemies and more potential foes that you don't even know about."

"So why are we doing it?" asked Ender. "The ship is dead, it's not going to follow our trail back to Earth. The human race isn't in danger. Let's just make our report and move on."

The others didn't even bother to answer such a ridiculous suggestion.