She grimaced. They were getting out of the trawler now, setting up for the descent. The Mars dawn stretched sharp shadows across a rosy plain. Next would come the cable descent. “Or a diversion, to lull us into complacency?”

“Could be.” Zuminski turned, shrugged as well as anyone could in a pressure suit. “Well, we’re not complacent anymore. Fraq is up to something—but what? The symbol-string certainly provoked the Marsmat. Intentionally?”

“That SETI message is clearly similar. If it came from Fraq’s civilization, sent several thousand years ago, then we now know the approximate location of his star. It’s a G2 about 1,480 light-years away.”

Zuminski attached his extra inputs and life support to his suit. The two teams, with the SETI crew a small fraction, swarmed around them, chattering. Busyness distracted. Plus the slow lurches of their humming transport.

Zuminski said, “And if we are right, that G-2 star has a wormhole nearby. That’s the first actual measurement—granted the premise that it’s his home world—of how far apart the wormhole complex links can be.”

“Is that a surprise? I thought wormholes could be of any length, because they’re really shortcuts in spacetime.” She got into the descent elevator, bottles and lines arranged. Life is so complicated when you don’t breathe the atmosphere! “Fraq could have traveled ten meters in his wormhole tunnel, then just popped through 1,480 light-years.”

“Makes you wonder why nobody did before.”

“Who says some of Fraq’s people didn’t?” She got into position with Xiaoling and Fraq, who was stiff and formal, nodding—a human gesture he had learned well. Here they were in an elevator and she, blithe Rachel, was talking about the alien when he stood a meter away. “Look, Fraq and his flock could just be the first ones who brought themselves to our attention, jetting in from the Oort cloud like innocents.”

Zuminski grinned at her through his somewhat grimy helmet bubble. “Beware of the innocents, my father used to say.”

“So assume he’s here to find out something from the Marsmat. What?”

“Can’t be more information on the wormhole network. They presumably know that.”

True, so… “Maybe it’s not information. Maybe it’s… things?”

Zuminski looked puzzled. “What?”

“Ummm. Mathists think of objects as just compact ways of carrying around information. So, to keep some information on Mars, subsurface so the Marsmat could somehow use it—how?”

He snorted. “Hard copy, must be. Really hard. A rock, maybe.” They started down. The cage rattled. Rock slid past.

Here came the vast underground. The available volume of warm, cavern-laced rock below Mars was comparable to the inhabitable surface area of Earth. Openings, from caverns down to pores in rock, suffered no wrenching from plate tectonics, since the Martian crust had frozen in place quite early. Plus, even the pores were larger, because of the lesser gravity. Plenty of room to try out fresh patterns, she thought. Over four billion years.

This time they went into another cavern network. Hassan had decided to address a different portion of the Marsmat, for safety reasons. So they lugged with them the graphical screen, onto which Fraq had loaded his second symbol-set with the help of the Descent Team.