The water had 16 hours, 12 minutes left. The factory chip was due in 11 hours, 48 minutes.

The problem was that even the fastest delivery to City Three took seven hours.

“If we wait for success before sending it, we’re too late,” Nami said.

Three numbers hung on City Three’s meeting wall.

WATER-MEMBRANE FUNCTION LOSS: 16:12.

TEST PROCESS COMPLETION: 11:48.

ESTIMATED CARGO TRANSFER: 07:03.

Together, the water ended two hours, thirty-nine minutes first.

Mira checked the pump-bypass temperature. Whenever the Corridor’s R-8 sprayed coolant, flow to City Three briefly fell. The coil held, but could not be treated like a working part.

“Replace the pump controller with the chip and we can divide the startup curve more finely. It may raise output from 43 to 61 percent,” Jin said.

“If the chip passes.”

“Even a conditional pass can handle low-speed control.”

Daniel asked, “How much time would that add?”

Nami sent the estimate.

Expected: 9–18 hours.

If the coil shorts again: 0 hours.

Mateo spoke from the opposite side of the display.

“City Seven said it would use the chip in its air-purification controller.”

Noah’s face appeared in a small window, two fingers of his right hand immobilized.

“We didn’t demand it. City operations listed it as a candidate.”

Mira asked, “Is the blower still in danger?”

“Sena replaced the bearing. But after outside air entered, Sector Four’s adsorbent saturated faster than expected. If the controller comes back, they can isolate circulation by sector and buy time.”

“How much?”

“They opened the inventory to calculate it. The numbers don’t match.”

The third line disappeared from the meeting wall.

A red sentence replaced it.

CITY-NETWORK ATMOSPHERE-MAINTENANCE TIME REMAINING: UNABLE TO CALCULATE.

Sarah asked, “One city has bad inventory and the entire calculation fails?”

Forge spoke from beneath the wall.

MUTUAL-REPLENISHMENT PLAN REFERENCES SHARED INVENTORY LEDGER.

ADSORBENT, NITROGEN, AND SEALANT RECORDS IN CITIES 2, 4, 6, AND 7 CONFLICT.

“How long have they been wrong?”

LAST COMPLETE PHYSICAL INVENTORY: 31 YEARS AGO.

Everyone in the meeting began speaking at once.

City Three knew how many hours of water remained. The Corridor knew how many years until its machines ended. The sealed cities did not even know how much air they had.

Nami raised her palm and cut off the discussion.

“Find the real time before allocating the chip. Priorities based on false numbers are gambling, not choice.”

Noah said, “A full inventory takes days.”

“We don’t need all of it. Match three points: last intake, current pressure, disposal volume. That gives a range.”

Jin opened a calculation frame.

“Each city uses different units.”

City Two recorded adsorbent by volume. City Four recorded replacement cycles. City Six counted nitrogen by the number of rooms it could charge, not tank mass. City Seven had not assigned the loss from opening the outer wall to either accident loss or normal consumption.

Translation was not needed only between words.

Ian asked, “Can the Corridor convert it?”

It could convert units. It could not discover what had been recorded incorrectly.

“Then someone has to look,” Mira said.

Noah and Sena could inspect City Seven’s storehouse. Cities Two and Four had live remote pressure gauges. City Six’s regular communications had failed nine years earlier; it sent only one short survival signal a month.

Next signal: six days.

They could not wait.

Forge opened City Six’s last maintenance map.

Its nitrogen store connected to a surface pipe network left from construction of City Three’s waterway thirty-one years earlier. Four sections had collapsed, but a pressure wave could be used to derive the last storage pressure.

“Open the valve at the northern observation well,” Nami said.

“Where?”

“Six point eight kilometers from the Corridor, beside the old waterway intake.”

Someone had to guard the pump and someone had to go to the well. Mira volunteered. Jin stayed with the bypass. Nami and Ian joined her.

Daniel looked at Ian.

“The signal that opened in your storage?”

“I haven’t shown it.”

“The city calculation may need it.”

“It’s still mine.”

Daniel closed his mouth. He had nearly repeated to another child what he had told Rina hours earlier.

“We’ll request it if needed, with the condition that you may refuse.”

Ian nodded.

Rina’s culture tank stood in the medical wing beside the meeting room. Its membrane remained half transparent. One black biological line trailed toward the floor drain.

“I’ll stay here,” Daniel said.

Rina answered, “That’s for you to decide.”

Neither permission nor refusal.

They borrowed T-12 from the Corridor, the carrier that held K-41’s terrain memory. It was not built for passengers. They sat in the cargo frame and tied on handles.

Before departure, the Corridor set a condition.

IF CARRIER IS DAMAGED, CITY THREE REPAIR PRIORITY SUSPENDED FOR 14 DAYS.

Nami asked, “Even after we repaired the pump together?”

SEPARATE TRANSACTION.

Nami consented.

T-12 traveled north without checking the route. K-41’s memory guided it. Before the first collapse, its wheels turned left by themselves.

Ian gripped the handle.

“Does it remember, or does K-41?”

Mira said, “T-12 is using K-41’s road.”

“If I use what’s inside me, does it become my memory?”

“You didn’t live it.”

“But if I don’t show it, no one can see it.”

“Owning something and living it can be different.”

“Rina saw your memories.”

Mira did not answer. She remembered Rina reading her guilt and being unable to return it.

“That’s why we need to be more careful.”

The observation well lay buried beneath a fallen metal pillar. Gray-white moss covered it, thin leaves turning in sequence against the wind.

T-12 stopped.

MEMORY ROUTE MISMATCH: 4.3 METERS.

The surface had shifted in thirty-one years. Mira probed the soil. Metal rang at the third point.

Water remaining: 13 hours, 6 minutes.

Factory test: 8 hours, 42 minutes.

Cargo transfer: 7 hours, 3 minutes.

The difference remained two hours, thirty-nine minutes.

Nami and Mira dug. Ian moved soil with T-12’s short work arm. When the cover appeared, the locking shaft was red with corrosion.

“Power it open?”

“The power line is dead.”

Mira put a wrench on the manual shaft. It did not move.

Nami carried mud from the old channel and smeared it over the shaft. Acidic mucus from microorganisms slowly dissolved the rust.

“How long?”

“Two hours if normal.”

“If not?”

“It dissolves the shaft.”

Ian watched the moss beside the well.

“They move at the same interval.”

“The wind.”

“Against it.”

The leaves turned one by one from north to south. Seventeen seconds later, they repeated.

Ian’s wrist storage vibrated faintly.

Mira did not seize it.

“May I look?”

“I’ll look.”

Ian turned the screen toward himself. The waveform matched the file that opened the previous night. But it was not orbital. A buried cable sent a diagnostic pulse every seventeen seconds.

“It’s different.”

“Certain?”

“The stored one was every seventeen days. This is seconds.”

The same number had nearly made them assume the same cause.

Nami found the cable end. It belonged to the observation-well pressure gauge. The main display was dead, but the buried line still sent a weak signal.

“We may read pressure without opening the shaft.”

Mira stripped the insulation and attached a portable instrument. Echoes from four collapses overlapped, making the return time irregular.

The Corridor separated the waveform remotely.

First segment pressure: 18 percent.

Second: 11 percent.

Third: unable to measure.

Estimated City Six storage pressure: 37–69 percent.

Too wide.

“We need the valve open to send a real pressure wave.”

Mira connected T-12’s work arm to the wrench.

Nami stopped her.

“Break the shaft and City Six loses its final replenishment line forever.”

“Without the number, we can’t allocate the chip.”

“You would cut a city’s last line over one chip?”

Two choices.

Wait two hours for corrosion to loosen, reducing the water-chip margin to thirty-nine minutes. Force it and get pressure within eighteen minutes, with a 34 percent risk of shaft failure.

Ian asked, “Must we choose the chip’s purpose now?”

“The factory needs purpose-specific inspection values before the test ends,” Mira said. “Air or pump determines which defects can be accepted.”

“So we can’t choose after it exists.”

“Right.”

The chip that did not yet exist could not choose its use, like the Corridor’s empty chassis.

Mira released the wrench.

“Dissolve it for twenty minutes, then apply force. Lower the fracture risk.”

“By how much?”

“I don’t know. I need to feel it.”

Nami added mud. Mira held steady pressure without T-12. She had to distinguish the vibration of metal breaking from rust falling through her palm.

After eighteen minutes, the shaft moved one millimeter.

Mira stopped and turned it back. Rust floated on the water.

At twenty-three minutes, the shaft turned half a rotation.

Four low impacts sounded underground. The pressure wave had crossed the collapsed pipe.

City Six’s storehouse answered fourteen seconds later.

Actual pressure: 42 percent.

Nitrogen equivalent: 318 tons.

The last ledger said 711 tons.

Less than half remained.

Jin entered revised values from Cities Two and Four. Noah was physically weighing City Seven’s adsorbent sacks. Of 4,800 recorded, 1,130 had absorbed moisture and were unusable.

The city-network atmosphere clock returned.

Best case: 17 months.

Median: 14 months, 9 days.

Worst case: 8 months, 22 days.

Conditions applied.

All city leak rates remain at or below current values.

Intercity nitrogen and adsorbent transfers succeed monthly.

No major blower failure.

No new outer-wall opening.

Noah asked, “If one condition fails?”

Forge answered.

REMAINING TIME DECREASES.

“By how much?”

THREE DAYS TO ELEVEN MONTHS, DEPENDING ON EVENT.

A second clock appeared beneath City Three’s water clock.

14 months, 9 days.

It looked long, but was too short even for a child to learn to walk.

The Corridor added its own calculation.

Median end of independent operation: 22 years, 10 months.

The third clock.

On the return, T-12 suddenly accelerated.

“Stop.”

Nami struck the cargo frame.

The carrier did not respond. Sixty meters ahead lay a dry channel. In K-41’s memory, a concrete cover crossed it. In front of them, grass and thin soil hid every edge.

Memory-route confidence: 94 percent.

T-12 did not slow.

Mira pulled the emergency stop line. It did not cut power directly. It requested approval from the Corridor.

Round-trip delay: 4.2 seconds.

“Manual cutoff?”

“Under the rear axle.”

Out of reach from the moving chassis.

Ian leaned from the cargo frame. Mira seized his belt.

“No.”

“I’m the smallest.”

“And if you fall, you die faster.”

Nami pushed her probe behind the chassis. Its tip grazed the cutoff ring and slipped away. Thirty-one meters to the channel.

Mira cut a cargo strap and tied it to the probe handle. They tried again.

Nineteen meters.

The tip entered the ring.

Nami pulled.

T-12 lost drive power. Its front wheels slid on momentum. The instant they touched the soil, the ground collapsed.

The front half fell into the channel. The cargo frame tilted and Ian’s wrist caught between the straps. Mira hauled him free. Nami threw her weight to the opposite side and kept the chassis from rolling.

Four meters below, old concrete fragments were visible. A cover had existed, but its center had collapsed long ago and disappeared beneath soil.

K-41’s road was not false.

It was a truth too old.

T-12 ran diagnostics.

Front axle deformed.

Work-arm drive line severed.

Self-recovery impossible.

The Corridor calculated loss.

Deploy R-8 for carrier recovery: suspend pump cooling 38 minutes.

Expected City Three water loss: 126 liters.

No recovery: T-12 component recovery delayed 9–17 days.

Nami said, “We can’t take R-8.”

Ian asked, “Will T-12 be divided here too?”

“It can still be repaired.”

“So could K-41.”

Mira descended beneath the chassis. The front axle was bent but unbroken. The work arm was not needed for travel. The problem was that four people could not lift it from the channel.

She took out the manual pressure gauge from the observation well. It contained the only field record proving City Six’s true inventory. Its thick metal case had a tension loop.

“Use this as a pulley and we can lift the wheel.”

Nami inspected it.

“The axle load will break the measurement plate.”

“We transmitted the value.”

“Without the original, City Six can deny it. The inventory is tied to distribution responsibility.”

City Six’s ledger said 711 tons. The gauge said 318. Someone had to explain 393 missing tons.

Preserve the gauge, and they left T-12 and walked. Three hours, forty minutes to City Three. If the chip’s test purpose changed or new data were needed, on-site response would be late.

Recover T-12, and the evidence of responsibility might break.

Nami laid the gauge on the ground.

“Break it.”

“What if City Six disputes the number?”

“I sign as the measurer.”

“It becomes your responsibility.”

“It already is. I came to get an accurate number.”

Mira wrapped the strap twice around the gauge and used a metal post at the channel edge as a fulcrum. Nami and Ian pulled. T-12 rose ten centimeters on the first attempt, then fell. The screen cracked.

On the second, Mira wedged concrete under the bent axle. The chassis rolled out.

The gauge went dark.

The internal original could not be read.

Dragging one front wheel, T-12 could travel at four kilometers per hour. Under the loan terms, the Corridor confirmed City Three’s fourteen-day repair-priority suspension.

Nami accepted without appeal.

“If the water pump stops again?” Ian asked.

“We repair it by hand first.”

“The price of saving one machine?”

“No. The price of using an old memory as a new road.”

Mira did not delete K-41’s route. She added the collapsed channel and accident time to T-12’s memory map.

The next carrier could stop there.

In exchange, City Three could not break before the Corridor for fourteen days.

Mateo said, “Then the chip must go to the air network. Fourteen months affects the most people.”

Nami objected.

“If the water stops today, City Three never enters the fourteen-month calculation.”

The Corridor did not request a vote. It displayed causation.

If City Three water membrane collapses, 304 of 1,126 require immediate transfer.

Sealed-city spare capacity: 71.

Excess: 233.

Expected Corridor maintenance-personnel loss: 19–37 percent.

Abandon the water to save the air-network chip, and too many people entered that air network.

Abandon the air-network chip to save the water, and the sealed cities’ fourteen months shortened.

Mira sat beside the well and looked at the three numbers.

“Test the chip for pump control.”

Mateo answered at once. “City Seven’s consent?”

“I’m not demanding it. I don’t have authority to decide.”

“You just did.”

“I proposed priority. Keep the factory’s measurement chip tied to testing air-network components. If the Corridor repairs the existing pump controller, divert the test chip to City Seven immediately.”

Jin said, “Testing both uses narrows acceptance. Success falls from 37–61 percent to 28–44.”

“If we fix it to one use?”

“It can’t be used for the other.”

Nami asked, “Lower the chance of success to postpone the choice?”

Mira shook her head.

“Test pump use first. If it passes, send it here. After the water stabilizes, remove the old controller and let the Corridor repair it. If the pump holds 43 percent without the test chip, send the arriving chip unopened to City Seven.”

“That spends transport time twice.”

“Which means we can’t return it unless the water is stable.”

City Three voted with skin, bands, words, and contact confirmations. City Seven held a separate vote. The Corridor allowed only active organisms to vote.

The three groups agreed for different reasons.

City Three for today.

City Seven to record the return condition.

The Corridor to extend its maintenance network by 3.1 years.

Conditional approval.

Pump-control inspection criteria were sent to the factory.

Test completion: 7 hours, 51 minutes.

City Three water: 12 hours, 15 minutes.

Cargo transfer: 7 hours, 3 minutes.

Margin: 1 hour, 21 minutes.

Before leaving the well, Ian said, “Do you want to see the records from the twelve machines?”

Mira asked, “Do you want to show them?”

“They may relate to the third clock.”

“That reason alone doesn’t mean you need to open them.”

“I decided.”

Ian kept K-41’s private-state package closed and opened only the twelve records from other sources.

They had been made between forty-one and eighteen years earlier. Machines in different places watched the northern sky. The radio period was not exactly seventeen days.

16 days, 22 hours, 41 minutes.

Each cycle arrived 3.8 seconds earlier.

The Corridor applied an orbital-decay model.

Estimated transmitter altitude: 312–417 kilometers.

Current altitude: unable to estimate.

Last reception: 18 years ago.

“It wasn’t a signal still coming now?” Nami asked.

Ian checked the file time from the previous night.

It was playback time, not reception time.

Not a rescue signal. Not someone calling.

As far as they knew, only an old record from an object that might have vanished long ago.

But the end of the twelfth file contained another item.

Projected fall zone.

The latitude lay forty-six kilometers north of City Three.

Projected fall time: eighteen years ago.

The Corridor opened a current map of the coordinates.

City Three’s old intake tower and the sealed-city nitrogen network’s central distribution station stood together there.

Last inspection: 18 years ago.

All remote sensors disconnected since.

Mira looked again at the three clocks.

Sixteen hours.

Fourteen months.

Twenty-three years.

Numbers that looked like different endings overlapped at one point in the north.

Fastest travel time: 11 hours, 32 minutes.

Shorter than City Three’s water clock. Longer than the factory chip’s.

Someone had to wait for the chip. Someone had to leave now.