“We have images of both species,” said the expendable. “Both worlds are regularly broadcasting visuals using primitive raster scans.” Holograms appeared in the middle of the cockpit. One species was low to the ground, with many limbs, all of them ­capable of grasping, and many of them with sharp claws or blades at their fingertips. The other species was tripedal, tall, and gracile, with a head crowned with vicious-looking horns. All three feet were prehensile, and one of them had two thumblike projections.

“Let me guess,” said Ram. “The low, scuttling one is the aggressive species that’s trying to take over the other side’s computers.”

“Wrong,” said the expendable.

“You wanted the roachlike one to be evil,” said Wheaton, delighted. “Easier to hate them!”

“Oh, I could easily hate them both,” said Ram. “For all we know, they teamed up to attack us. We never saw who was piloting those aircraft.”

“It’s too dangerous to go into the future to see what happens,” said the alpha mouse. “Our counterparts on the twentieth ship are still searching to make sure they’ve cleaned out all the intrusions.”

“The mice don’t want to go into the future to learn any more,” said Noxon. “If they’re scared of the aliens’ capabilities, we’d be crazy to make the attempt.”

“So we just go blindly backward,” said Ram.

“To find out if we can leave the flora and fauna on either world intact,” said Wheaton.

“We can,” said Noxon. “We can always decide not to establish colonies on either world.”

“That’s not an option,” said Ram. “We’re here to neutralize the threat. We have no way of monitoring whether we’ve succeeded without establishing a permanent, technologically powerful presence.”

“That’s not really true,” said Noxon. “For instance, we could drop off the mice a million years ago and then pop back to this time to see where we stand.”

Ram laughed. “We’d find that the mice were completely prepared to destroy us, take over our ship, fly back to Earth, and take over everything.”

“We would never,” said the alpha mouse.

“I was just pointing out that if we establish human colonies, it’s because we want to, not because there’s no other way,” said Noxon.

“Well,” said Ram, “whatever we do, I don’t propose to leave it all up to the mice.”

“The other ships have all decided to go back and test the proteins on both worlds,” said the expendable.

“How do we divide the fleet?” asked Ram.

“The computers have already divided the ships randomly into two groups of ten. We’re in the group that stays at this near world, while the others jump the fold to the far one.”

“The one with the tripods,” said Wheaton. “That’s a shame—I was most interested in studying them.”