“All right then,” she said, mouth tight. “I’ll see what’s up.”

Badim hugged her. “It won’t last forever,” he said. “It won’t even last very long. Things are going to change.”

So they trudged together down the narrow road through the forest that led from the tram stop in west Nova Scotia to the Fetch. Badim could see Freya was looking nervous, so he suggested they go out to the dock by the corniche, where they could look down the length of Long Pond and see most of their world, so familiar to them, now flush with the mellow light of a late-autumn afternoon. They did that, and Freya exclaimed to see it; now to her it looked dense with forest, with the boreal mix that on Earth wrapped the entire Northern Hemisphere in a dark green band, covering more land than any other ecosystem. And the Fetch looked so big and crowded, a real city, with too many people, too many windows, too many buildings.

Devi was cooking dinner when they walked in. She saw Freya and eeked with surprise, then shot a glance at Badim.

Freya said, “I’m here to help,” and wept as they hugged. She had to lean down quite a bit to do this; her mother seemed to have shrunk in the time she had been away. Three years is a long time in human terms.

Devi pulled back to look up at her. “Good,” she said, wiping the tears from her eyes. “Because I can use the help. I’m sure your father told you.”

“We’ll both help. We’ll make landfall together.”

“Landfall!” Devi laughed. “What a word! What a thought.”

Badim said what he always did, in a pirate voice: “Land, ho!”

And it was true that in the screens showing the view ahead of the ship, there was a very bright star now, quite piercing in the black of space, too bright to look at directly without filtering; and with the filters applied one could see it was a little disk, which made it far bigger than any other star.

Tau Ceti. Their new sun.

After that, Freya started going out with Devi on her trips again. Her behaviors were no longer those of a child in tow, but rather those of a personal assistant, student, or apprentice. Badim called it shadow learning, and said it was very common, indeed perhaps the chief method of teaching in the ship, more effective than what they did in the schools and workshops.

Freya helped Devi in every way she could, and listened to her for as long as she could concentrate, but it was clear she became distracted when Devi went on at length. Devi’s days were long, and she had the ability to pay attention to something for as long as she could stay awake. And she liked to work.

The physical form of her work mostly consisted of reading screens and then talking to people about what she found. Spreadsheets, graphs, schematics, diagrams, blueprints, flowcharts, these Devi inspected with great intensity, nose sometimes so close it left a mark on the screen. She could spend hours viewing things at nanometer scale, where everything pictured on the screen was gray and translucent, and slightly quivering. This Freya found hard to do for long without getting a headache.

Only a small proportion of Devi’s time was spent looking at real machines, real crops, real faces. These were moments when Freya could be more helpful; Devi was stiff these days, and Freya could run about and get things, pick things up and carry them. Carry Devi’s bags for her.

Devi noticed what Freya preferred to do, and said that Freya had been enjoying her life more before she came home. She grimaced as she said this, but as she told Freya, there was nothing she could do about it; if Freya was going to help her, shadow her, then this was her life. This was what Devi’s work consisted of, and she couldn’t change it.

“I know,” Freya said.

“Come on, today’s the farm,” Devi said one morning. “You’ll like that.”

The farm in Nova Scotia referred actually to several farming tracts scattered through the biome’s forest. The largest parcel, where they headed, was devoted to growing wheat and vegetables. Here Devi looked mostly at people’s wristpads as they spoke to her, but she also walked out into the row crops and inspected individual plants and irrigation elements. They met with the same people they always met with here; there was a committee of seven who made this operation’s agricultural decisions. Freya knew each one of them by name, as they had taught her favorite parts of school in her childhood.

Out in the farm’s greenhouse lab, Ellen, the leader of their soil studies group, showed them the roots of a cabbage. “These have been tweaked to have extra AVpl, but even so, it looks like lazy root to me.”

“Hmm,” Devi said, handling the plant and eyeing it closely. “At least it’s symmetrical.”

“Yes, but look how weak.” Ellen snapped the root in two. “And they’re not acidifying the soil like they used to either. I don’t get it.”

“Well,” Devi said, “it could just be another phosphorus problem.”

Ellen frowned. “But your fixer should be compensating for that.”

“It did, at first. But we’re still losing phosphorus somewhere.”

This was one of Devi’s most frequent complaints. They had to keep their phosphorus from getting bound with the iron, aluminum, or calcium in the soil, because if that happened the plants couldn’t unbind it. Keeping it unbound was hard to do without wrecking the soil in other ways, so the solution in Terran agriculture was to keep applying more of it in fertilizers, until the soil was saturated, at which point some would stay free for roots to take in. In the ship, that meant the need for phosphorus was such that its overall cycle had to be closed in its looping as tightly as possible, so they didn’t lose too much of it. But they did, despite all their efforts; it was what Devi called one of the Four Bad Metabolic Rifts. As a result, it was turning out that the people who had originally stocked the starship had not given them as much of an overstock of phosphorus as they had of many other elements; why they had done that, Devi said, she would never understand.

So they did everything they could think of to keep the phosphorus cycle looping without losses. Some phosphorus in their waste treatment plant combined with magnesium and ammonium to make struvite crystals, which were a nuisance to the machinery, but which could be scraped off and used as fertilizer, or broken up and combined with other ingredients to make other fertilizers. That put that phosphorus back into the loop. Then the wastewater was passed through a filter containing resin beads embedded with iron oxide nanoparticles; these binded to the phosphorus in the water, in a proportion of one phosphorus atom to four oxygen atoms, and the saturated beads could later be treated with sodium hydroxide, and the phosphorus would be released for reuse in fertilizers. The system had worked well for many years; they filtered the phosphorus at a 99.9 percent capture rate; but that tenth of a percent was beginning to add up. And now their reserve storage of phosphorus was nearly depleted. So they had to find some of the phosphorus that had gotten stuck somewhere, and return it to the cycle.

“It’s surely bound in the soil,” Ellen said.

“We may have to process all the soil in all the biomes,” Devi said, “plot by plot. See how much we’re finding after a few plots, and then see if that’s where it is.”

Ellen looked appalled at this. “That would be so hard! We’d have to pull all the irrigation.”

“True. We’ll have to take it out and then replace it. We can’t farm without phosphorus.”

Freya moved her lips in time with her mother’s as Devi concluded, “I don’t know what they were thinking.”