“There you are,” said Savi, striding down the slope toward them. She closed her fist and what looked like a palm finder-field blinked out.

“Time to go on?” asked Odysseus, speaking to Savi but glancing toward Hannah as if they were old conspirators.

“Time to go on,” said Savi.

Three weeks into the voyage west up the river—inland sea, really—of Valles Marineris, and Mahnmut was close to losing his moravec mind.

Their felucca, crewed by forty little green men, was just one of many ships plying their way east or west in the flooded rift valley or north-south up or down the estuary opening onto the Chryse Planitia Sea of the Northern Tethys Ocean. In addition to a score of other LGM-crewed feluccas, they had passed at least three 100-meter-long barges each day, each hauling four great, uncarved stones for heads, all headed east from the cliff quarry on the south side of Noctis Labryinthus at the west end of Valles Marineris, still some 2,800 kilometers ahead of Mahnmut’s west-bound felucca.

Orphu of Io had been rolled aboard and secured on the lower mid-deck, hidden from aerial view by a raised tarp, tied down next to the major pieces of cargo and other items recovered from The Dark Lady. Even the thought of his submersible—left behind in the shallow sea cavern along the Chryse Planitia coastline some 1,500 kilometers behind them—depressed Mahnmut.

Until this voyage, Mahnmut hadn’t known that he was capable of depression—capable of feeling such a terrible emotional malaise and sense of hopelessness that could leave him with almost no will and even less ambition—but the violent separation from his sub had shown him just how low he could feel. Orphu—blinded, crippled, hauled aboard like so much useless ballast—seemed in good spirits, although Mahnmut was learning how carefully and rarely his friend showed his true feelings.

The felucca had arrived, as promised, early that next Martian morning after their arrival on the coast, and while the LGM were man-hauling poor Orphu aboard, Mahnmut had gone down into the flooded sub several times, pulling out all the removable power units, solar cells, communication equipment, log disks, and all the navigation gear that he could haul.

“You swam naked out to the wreck and stuffed your pockets with biscuits before swimming back, eh?” Orphu had said that morning after Mahnmut told him about the salvage efforts.

“What?” Mahnmut wondered if the battered Ionian had finally lost his mind.

“Little continuity error in Defoe’s Robinson Crusoe,” rumbled Orphu. “I always enjoy continuity errors.”

“I never read it,” Mahnmut said. He was in no mood for banter. Leaving The Dark Lady behind was tearing him apart.

They discussed his reaction during the first three weeks of their voyage, since they had little to do aboard the felucca except discuss things. The short-range radio receiver transmitter that Mahnmut had grafted onto Orphu’s commline jack worked well.

“You’re suffering from agoraphobia as much as from depression,” said Orphu.

“How so?”

“You were designed, programmed, and trained to be part of the sub, hidden under Europan ice, surrounded by darkness and crushing depths, comfortable in your tight spaces,” said the Ionian. “Even your short forays on the ice surface of Europa didn’t prepare you for these vast vistas, distant horizons, and blue skies.”

“The sky’s not blue right now,” was all that Mahnmut said in response. It was early morning, and, like most mornings, Valles Marineris was filled with low clouds and thick fog. The LGM had furled the felucca’s sails and were moving ahead by oars alone—thirty of the little green men rowed, fifteen on a side, seemingly indefatigable—whenever the wind didn’t move the two-masted, lateen-rigged sailing ship. Lanterns glowed on the bow, forward mast, both sides, and stern, and the felucca was barely moving. This section of the Valles Marineris was more than 120 kilometers wide and the section they would soon be entering would be 200 kilometers across—an inland sea rather than river, where, even on clear days, the high cliffs of the north or south banks of the waterway would be invisible in the distance—but there was enough LGM ship traffic along these channels to justify such caution in the fog.

Mahnmut realized that Orphu was right—that agoraphobia was part of his problem, since he felt the depression most acutely on the clear days where the views were unlimited—but he also knew that it was more complicated than being separated from the secure crèche and sensory jacks of his ship. Mahnmut was—had always been—a sea captain, and he knew from his own history programming and later reading that nothing hurt captains more than the loss of their ships. On top of that, he’d been tasked with an important mission—delivering Koros III to the oceanward base of Olympus Mons—and he had failed miserably. Koros III was dead, as was Ri-Po, the moravec who should be waiting in orbit to receive, interpret, and relay Koros’s important reconnaissance data.

To whom? How? When? Mahnmut didn’t have a clue.

They talked about that as well during their weeks of quiet voyaging. It was even quieter at night, since the LGM went into hibernations as soon as the sun set, securing the felucca with a complicated sea anchor—Mahnmut had done echo soundings and determined that the water under them was more than six kilometers deep—and not stirring again until sunlight touched their green, transparent skin the next morning. It seemed obvious that the LGM gained energy solely through sunlight, even from the diffused light through morning fog. Certainly Mahnmut had never seen any of the little green men eat or secrete anything. He could ask them, but even though Orphu hypothesized that the individual LGM did not really “die” after communication—that the little green men were an aggregate consciousness rather than an assembly of real individuals—Mahnmut did not trust the hypothesis enough to reach into another little green person’s chest, grip what could be his heart, and ask questions that might be deferred until another day.

But Mahnmut had no reservations about asking Orphu questions.

“Why did they send us?” he asked on their tenth day. “We don’t understand the mission and aren’t suited to carry it out even if we did know what we’re supposed to do. It was madness to send us here this ignorant.”

“Moravec administrators are used to compartmentalizing duties and assigning specialties,” said Orphu. “You were the best they could find to drive Koros III to the volcano. I was the best moravec they could get to service the spacecraft. They never considered the possibility that you and I would be the team left to do the work of the other two.”

“Why not?” said Mahnmut. “They must have known that the mission would be dangerous.”

Orphu rumbled softly, “Probably they thought that if was all or nothing—that we’d all die if worse came to worst.”

“We almost did,” muttered Mahnmut. “We probably will.”

“Describe the day,” said Orphu. “Has the fog lifted yet?”

The days and the scenery and the nights were beautiful. Mahnmut’s knowledge of breathable-atmosphere worlds came exclusively from his data bank records of Earth, and this terraformed Mars was an interesting variation.

The skies varied from a bright light blue at midday to a pink-red sky at sunset that sometimes shifted hues toward a pure gold light that infused everything with radiance. The sun itself looked significantly smaller than the sun seen from Earth in old video-records, but it was immensely larger and brighter and warmer than any sun known by Galilean moravecs in the last two thousand e-years. The breeze was soft and smelled of salt sea and—sometimes, shockingly—of vegetation.