The returning sunwalkers crowd onto the loading platform as the city nears it. Some have been out for weeks, or even the months it would take to make a full circumambulation. When the city slides by, its lock doors will open and they will step right in.

That is soon to occur, and Swan should be there too. Yet still she stands on her promontory. More than once she has required retinal repair, and often she has been forced to run like a rabbit or die. Now it will have to happen again. She is directly south of the city, and fully lit by horizontal rays, like a silver flaw in one’s vision. One can’t help shouting at such rashness, useless though it is. Swan, you fool! Alex is dead—nothing to be done about it! Run for your life!

And then she does. Life over death—the urge to live—she turns and flies. Mercury’s gravity, almost exactly the same as Mars’s, is often called the perfect g for speed, because people who are used to it can careen across the land in giant leaps, flailing their arms for balance as they bound along. In just that way Swan leaps and flails—once catches a boot and falls flat on her face—jumps up and leaps forward again. She needs to get to the platform while the city is still next to it; the next platform is ten kilometers farther west.

She reaches the platform stairs, grabs the rail and vaults up, leaps from the far edge of the platform, forward into the lock as it is halfway closed.

SWAN AND ALEX

Alex’s memorial ceremony began as Swan was straggling up Terminator’s great central staircase. The city’s population had come out into the boulevards and plazas and were standing in silence. There were a lot of visitors in town as well; a conference had been about to begin, one that had been convened by Alex. She had welcomed them on Friday; now on the following Friday they were holding her funeral. A sudden collapse, and they hadn’t been able to revive her. And so now the townspeople, the diplomat visitors: all Alex’s people, all grieving.

Swan stopped halfway up the Dawn Wall, unable to go on. Below her rooftops, terrace patios, balconies. Lemon trees in giant ceramic pots. A curved slope like a little Marseilles, with white four-story apartment blocks, black iron-railed balconies, broad boulevards and narrow alleys, dropping to a promenade overlooking the park. All crowded with humanity, speciating right before her eyes, each face intensely itself while also a type—Olmec spheroid, hatchet, shovel. On a railing stood three smalls, each about a meter tall, all dressed in black. Down at the foot of the stairs clustered the sunwalkers who had just arrived, looking burnt and dusty. The sight of them pierced Swan—even the sunwalkers had come in for this.

She turned on the stairs and descended, wandered by herself. The moment she had heard the news, she had dashed out of the city onto the land, driven by a need to be alone. Now she couldn’t bear to be seen when Alex’s ashes were scattered, and she didn’t want to see Mqaret, Alex’s partner, at that moment. Out into the park, therefore, to wander in the crowd. All of them standing still, looking up, looking distraught. Holding each other up. There were so many people who had relied on Alex. The Lion of Mercury, the heart of the city. The soul of the system. The one who helped and protected you.

Some people recognized Swan, but they left her alone; this was more moving to her than condolences would have been, and her face was wet with tears, she wiped her face with her fingers repeatedly. Then someone stopped her: “You are Swan Er Hong? Alex was your grandmother?”

“She was my everything.” Swan turned and walked off. She thought the farm might be emptier, so she left the park and drifted through the trees forward. The city speakers were playing a funeral march. Under a bush a deer nuzzled fallen leaves.

She was not quite to the farm when the Great Gates of the Dawn Wall opened, and sunlight cut through the air under the dome, creating the usual horizontal pair of yellow translucent bars. She focused on the swirls within the bars, the talcum they tossed up there when they opened the gates, colored fines floating on updrafts and dispersing. Then a balloon rose from the high terraces under the wall, drifting west, the little basket swaying under it: Alex; how could it be. A surge of defiance in the music rumbled up out of the basses. When the balloon entered one of the yellow bars of light, the basket blew apart in a poof, and Alex’s ashes floated down and out of the light, into the air of the city, growing invisible as they descended, like a shower of virga in the desert. There was a roar from the park, the sound of applause. Briefly some young men somewhere chanted, “A-lex! A-lex! A-lex!” The applause lasted for a couple of minutes, and arranged itself as a rhythmic beat that went on for a long time. People didn’t want to give it up; somehow that would be the end, they would at that very moment lose her. Eventually they did give it up, and lived on into the post-Alex phase of their lives.

She needed to go up and join the rest of Alex’s family. She groaned at the thought, wandered the farm. Finally she walked up the Great Staircase, stiffly, blindly, pausing once to say, “No, no, no,” for a time. But that was pointless. Suddenly she saw: anything she did now would be pointless. She wondered how long that would last—seemed like it could be forever, and she felt a bolt of fear. What would change to change it?

Eventually she pulled herself together and made her way up to the private memorial on the Dawn Wall. She had to greet all those who had been closest to Alex, and give Mqaret a brief rough hug, and withstand the look on his face. But she could see he was not home. This was not like him, but she could fully understand why he might depart. Indeed it was a relief to see it. When she considered how bad she felt, and then how much closer Mqaret had been to Alex than she had been, how much more of his time he spent with her—how long they had been partners—she couldn’t imagine what it would feel like. Or maybe she could. So now Mqaret stared at some other reality, from some other reality—as if extending a courtesy to her. So she could hug him, and promise to visit him later, and then go mingle with the others on the highest terrace of the Dawn Wall, and later make her way to a railing and look down at the city, and out its clear bubble to the black landscape outside it. They were rolling through the Kuiper quadrant, and she saw to the right Hiroshige Crater. Once long before, she had taken Alex out there to the apron of Hiroshige to help with one of her goldsworthies, a stone wave that referenced one of the Japanese artist’s most famous images. Balancing the rock that would be the crest of the breaking wave had taken them a great number of unsuccessful efforts, and as so often with Alex, Swan had ended up laughing so hard her stomach hurt. Now she spotted the rock wave, still out there—it was just visible from the city. The rocks that had formed the crest of the wave were gone, however—knocked down by the vibration of the passing city, perhaps, or simply by the impact of sunlight. Or fallen at the news.

A few days later she visited Mqaret in his lab. He was one of the leading synthetic biologists in the system, and the lab was filled with machines, tanks, flasks, screens bursting with gnarled colorful diagrams—life in all its sprawling complexity, constructed base pair by base pair. In here they had started life from scratch; they had built many of the bacteria now transforming Venus, Titan, Triton—everywhere.

Now none of that mattered. Mqaret was in his office, sitting in his chair, staring through the wall at nothing.

He roused himself and looked up at her. “Oh, Swan—good to see you. Thanks for coming by.”