1.

Xiaoming1 saw the mothership for the first time when she was a little girl.

It was a large vessel, so immense that its profile blocked half the sky. From the land it gathered steel and iron; from the sea it collected plastics. It devoured everything and gave it new life. When the mothership’s hold yawned open, countless islands spilled out of its belly, like a spawning salmon.

“What is that?” she asked, clutching her mother’s dress.

“Our new home,” replied Dengbi. Xiaoming could see the churning waves reflected in her mother’s eyes, and she would always remember that bright glow.

Dengbi ended up picking a pure white island for them. It was slender and tipped at both ends, like a willow leaf. In length it was just under twenty meters, and its widest point measured no more than six meters. The sides and ends of the island were equipped with mortise-and-tenon joints so that all they needed was to buy a locking bar from the harbor, and they could secure the island anywhere in the city.

Dengbi then ordered a 3D printer. Designing, refining, printing—she built a two-story house on and inside the island, complete with furniture, plumbing, and wiring, the composite material drying in the bright sunlight. The lower floor was underwater, where the family could rest and sleep. There were large portholes on both sides, with good views of the passing fish. The bed and mattresses were also printed from composites, with honeycomb structure to be bouncy. The upper floor poked above the waves and housed the helm provided by the mothership. Dengbi augmented this with tables and chairs for a living area, counters and stoves for the kitchen, as well as workbenches. Finally, she secured the solar panels to the roof and fed the wires through printed channels in the walls, plugging them into screens and other electronics. She was done.

Viewed from above, East Sea City resembled a large tree. The various streets, major and minor, were the branches, big and small, spreading from a central trunk. Their island was a single leaf at the very edge of the city-tree. The ocean, divided by the branches and island-leaves, became rivers and lakes in the city. Every day, Xiaoming rode her bike along the spinelike road to school. Since the road was formed from islands connected from end to end, it rose and fell with the rhythm of the ocean’s breath, so that she had to match the undulations in her pedaling.

Xiaoming knew that her mother had been born on land. From time to time, she imagined their island casting off from the city, adrift, perhaps on an adventure back to the continent, like her father.

“That’s a long journey, and much too dangerous,” Dengbi said. Other than the very first day when she had bought the island from the mothership and guided it to the edge of the city, she never touched the helm again.

Land was indeed a dangerous place. At first, the street their island was attached to was largely empty, with few homes. But by the time Father returned to East Sea City on a ferry, the branch was filled to the brim, with no room for even a single additional leaf-island, whatever the shape. Xiaoming heard her parents sigh and speak of a “disastrous flood” on land, which seemed terrifying. She didn’t really get it, however. In school, she had learned that the continents were like larger, more solid versions of East Sea City, and they drifted around slowly, separating and reuniting over millions of years. If the world had always been adrift, why did people fear water?

After Zhuguang, her sister, was born, the island-home felt cramped. Father wanted to copy their neighbors and add another story. But Dengbi did the calculations and told them that it was unsafe. “It would be fine so long as we remained in the city,” she said. “However, if we decided to leave and sail the ocean, the island would sink as soon as we met a storm.”

They had to modify their plans. Dengbi asked the drones to deliver several drums of composite materials and hooked them up to the 3D printer. The printer moved around on eight slender and nimble legs, each tipped with a sucker, like a spider weaving a web. After several days of creaking and cranking, the printer made a tiny workshop on top, which also served as a lookout post. Xiaoming loved to go there in the evenings, especially on the eve of a storm, when the dusk clouds were torn into wisps by the wind and then dyed shades of glowing purple-crimson by the setting sun.

“Hey! Let’s go swimming before it’s dark,” Zhuguang called to her. That was Dengbi’s rule: the two girls couldn’t leave the island after it got dark. Xiaoming glanced at the colorful clouds on the horizon and thought they had maybe fifteen minutes left. She slid down the mast to the deck, grabbed her little sister’s hand, and together, they dived into the sea.

2.

Father returned from a trip to city center. “The politicians are thinking of dividing East Sea City,” he said.

“There are just too many people.” He flipped the fish in the pan, and droplets of oil danced in the glow of the kitchen lamp. Xiaoming went to take a bath while Zhuguang stood by the stove, watching the fish cook with hungry eyes. Dengbi kept her VR headset on as she worked. She was now an interior designer. Under her skilled hands, each blank island turned into a home, a store, a school….

“Why does that require dividing the city?” Dengbi took off her headset and frowned at her husband.

“There’s only one center for all of East Sea City, which means that the spatial structure isn’t operating very efficiently. It’s not economical.” He saw Dengbi’s expression and added, “The key is that the infrastructure has been pushed to the limit. Our desalinization system can only support a certain population, but there are still more immigrants fleeing here from land. The politicians are trying to decide what to do: should we scatter the newcomers everywhere like dandelion seeds, or should we add another set of infrastructure and undergo urban cellular mitosis?”

Dengbi chuckled. “You make it sound so simple.”

By the time her parents’ conversation, muffled by the walls, reached Xiaoming in the bathtub, she could only discern three words: “East Sea City,” “dandelion,” and “mitosis.” But that was enough. Dandelions were rare in East Sea City. They could occasionally be found among the small plots of grass tucked into the corners of city gardens, and were treasured by Zhuguang—in fact, the first word she ever said was “blow,” in response to which Xiaoming would take a deep breath and blow all the seeds of a dandelion puff ball into the sky, until the miniature parachutes scattered to who knew where. As for mitosis, she had just learned about it in class that day: The nucleus on the screen broke apart so that the chromosomes could separate and gather to the two poles of the cell until a new wall formed in the middle, dividing what was one cell into two independent individuals. Here, Xiaoming suddenly had a vision of the city itself as a life form, a giant monster lying prostrate over the surface of the ocean, endowed with countless tentacles and suckers—maybe the twin towers at the city center were its eyes!

“Time for dinner!” Zhuguang pounded on the bathroom door. “Come out!”

Xiaoming immersed herself in the tub and looked through the porthole. Outside, the storm had arrived, and churning waves filled much of the view. The sea seemed to have been processed by a grey-scale filter: the foamy wave tips were blindingly white, the sky was pitch black, and the rest of the water was in shades of grey. There was no moon, so the world was deprived of even a hint of golden light. She recalled the disaster survival class from school: In the event of a catastrophe, each island wouldn’t separate and be on its own. Instead, each “tentacle-branch” was designed to break off at the base, and the island-leaves attached to that branch were supposed to adjust their alignment so that instead of hooking onto the branch by their tips, each individual island would be securely attached on one side. Every tentacle would thus transform from a loose imitation of a fish skeleton into a tightly bundled shuttle-raft. After their street had filled with neighbors, they’d conducted a drill to practice the maneuver. Since there were too many islands for all to be attached directly to the spine of the street, they had to move the islands around to attach in layers. Dengbi’s island was in the outermost layer, and its tenon-hooks were attached to the side of a neighboring island.

The real answer has to be a sea-monster, she decided as she got out of the tub. The city will be like the octopuses that drop arms before a predator and abandon the excess tentacles to the sea.

“I’ll be right there,” she said to Zhuguang through the door.

3.

“The mothership is coming,” Dengbi whispered to Xiaoming.

The mothership was a secret the two shared because they were the only ones to witness it the first time ten years ago. Now, they were also the first to know of its return. The Planning Committee had sent a message to Dengbi, inviting her to join the design of the new public buildings.

“They want a new commercial street, a new hospital, and a new athletic complex,” Dengbi told Xiaoming. “That’s a lot of space! There aren’t enough empty islands in the city. I’m sure the mothership will be coming.”

Her mother’s words lingered in Xiaoming’s mind. As school ended, she tried hard to recall the mothership, but then she saw the massive vessel looming beyond the end of the street. Floating on the sea at a distance, the hemispherical structure resembled half of a dandelion puff ball. A breeze rose, and a swarm of drones took off from the mothership, heading toward East Sea City. No, it looked nothing like the ship in Xiaoming’s memory.

Xiaoming jumped off her bike and let it fall to the side of the street. She dived into the sea and swam frantically for home, only coming up for air in the seams between islands. Finally, she reached her home, the little white island. She placed one hand on the tenon-hook, her thumb on the locking bar release. She took out the small hammer she had hidden inside. She knew that if she freed the locking bar, the island would disconnect from the rest of the city and be able to escape on its own under auto-pilot.

But the drones didn’t approach her island. They clustered at the end of the street, or even further, swirling around like a solid cyclone.

“What is that sound?” Dengbi emerged from below. Still wearing her VR headset, she climbed onto the deck. It took her a while before she realized Xiaoming was in the water nearby. “Oh, don’t be scared,” she said to her daughter. “It’s the mothership—upgraded.”

Xiaoming sighed with relief. She put the hammer in her pocket and climbed onto the island, standing next to her mother. The upgraded mothership was not nearly as impressive in size as the ship in her memory. Dengbi explained to her that the old mothership had to construct whole islands inside itself, but the new mothership could build a floating city on the open sea just using its drones and materials.

Father and Zhuguang came onto the deck as well. The whole family sat on the gunwale and watched the activity. Dengbi gave Xiaoming her VR headset so that she could watch the drones through the telephoto lens. There were many types. Some, like flocks of seagulls, collaborated to carry heavy machinery and steel beams; others, much smaller, resembled home-use 3D printers, clambering about with propellers and slender legs; still others bobbed on the surface like small, round coracles, bringing an endless stream of composite materials to the constructing drones. The hubbub lasted long into the night, when glowing lights from the drones lit up the sea like a multitude of stars. Even when Dengbi called Xiaoming to come inside the island for bed, the drones were still working.

Xiaoming was up before the sun so she could continue her observation. While running toward the mothership, she realized that the street was oddly stable and flat, extending endlessly into the distance, fading into the blue-grey fog. The street no longer seemed to be made of separate islands.

She stopped.

Perhaps the road surface underfoot is freshly constructed, and the other end is already connected to the nucleus of the new “cell,” she thought. The old nucleus and the new are straining to pull apart. That’s why the road is so flat and straight, like a belt under tension.

She wanted to tell her mother of this new discovery. But as she reached home, a drone stopped next to her island.

“Breakpoint,” the drone chirped.

Xiaoming walked next to the drone and saw that it was marking the ground: a thin line. “What are you doing?”

“This is the breakpoint,” the drone said. “I’m going to melt the road here and separate the islands on each side. What are you doing here?”

“That’s my home.” Xiaoming pointed to the white island.

“You live right on the breakpoint,” the drone said. “Which side do you want to be on? The old East Sea City, or the new? There’s still enough time for you to decide.”

Xiaoming felt the heat in her ears. She was about to make an important decision. She looked at the line on the ground. It was just on the other side of the white island, closer to the old city. The drone had placed them in the new city.

“I like the way you’ve done it,” Xiaoming said.

A flaming tongue shot out of the drone. The composite surface melted, revealing the islands under the street. Xiaoming knelt to watch. The drone stuck out a slender arm to release the tenon-hooks.

“Let me,” she said. She climbed down into the seam between the islands and struck the locking bar with her hammer until it loosened and came out, releasing the tenon-hook. Xiaoming stood with one leg on each side of the widening gap between two islands. At the rise of the next wave, she pushed off and sent the old world away.

“Come up! Hurry!” the drone told her.

The sea surged into the gap, instantly turning it into a river, and then a lake, and finally, the twin towers of old East Sea City became the eyes of a faraway monster. Xiaoming climbed onto the island with the drone’s help and stood at the shore of the new world. With the tension that had kept the road so taut gone, the street had relaxed back into a soft spine, rising and falling with the ocean’s breath.

The morning fog dissipated, and the mothership reappeared on the horizon. Xiaoming asked the drone, “What’s it like inside the mothership?”

The drone didn’t answer. It had completed its mission; now it was time to take off and go home. Xiaoming realized that she had left her bike in the old world, but that didn’t bother her. She knew she could walk on her own feet to the very heart of the ocean.