In the winter they made forays onto the surface, to the nearby crater where Nadia was building a shelter, and the dark ice-spangled dunes beyond. But when the fog hood lifted they had to stay under the dome, or at most go out to the window gallery. They weren’t to be seen from above. No one was sure if the police were still watching from space or not, but it was best to be safe. Or so the issei said. Peter was often away, and his travels had led him to believe that the hunt for hidden colonies must be over. And that the hunt was hopeless in any case. “There are resistance settlements that aren’t hiding at all. And there’s so much noise now thermally and visually, and even over the radio,” he said. “They could never check all the signals they’re getting.”

But Sax only said, “Algorithmic search programs are very effective,” and Maya insisted on keeping out of sight, and hardening their electronics, and sending all their excess heat deep into the heart of the polar cap. Hiroko agreed with Maya on this, and so they all complied. “It’s different for us,” Maya said to Peter, looking haunted.

There was a mohole, Sax told them one morning at school, about two hundred kilometers to the northwest. The cloud they sometimes saw in that direction was its plume— big and still on some days, on others whipping off east in thin tatters. The next time Coyote came through they asked him at dinner if he had visited it, and he told them that he had, and that the great shaft of the mohole penetrated to very near the center of Mars, and that its bottom was nothing but bubbling molten fiery lava.

“That’s not true,” Maya said dismissively. “They only go down ten or fifteen kilometers. Their floors are hard rock.”

“But hot rock,” Hiroko said. “And twenty kilometers now, I hear.”

“And so they do our work for us,” Maya complained to Hiroko. “Don’t you think we are parasites on the surface settlements? Your viriditas wouldn’t get far without their engineering.”

“It will prove to be a symbiosis,” Hiroko said calmly. She stared at Maya until Maya got up and walked away. Hiroko was the only one in Zygote who could stare Maya down.