Page 51 of A.I.AM.

“Or someone maintaining the standpipe.”

Code brushed clay from a cast plate. The manufacturer’s date was 1964. Beneath it, a second plate had been screwed into the concrete upside down. Pigsty bent sideways to read it.

“Do not operate without upstream pressure.” Tanner glanced at the dry channel.

“We don’t have any.”

“Good. Clear authorization.” Pigsty turned the wheel. It resisted, groaned, then released with a deep metallic cough. Nothing else happened. Code listened against the pipe.

“Empty.”

“A thrilling result,” Pigsty said. “Write it in the after-action report.”

From the north came Ace’s whistle. They crossed the scale road to find him beside an old cattle guard half buried in grass. AJ held something thin between two fingers.

“Copper shim,” AJ said. “Placed under the fourth crossbar. Worn on one edge.”

“Stylus?” Carl asked.

“Bearing surface. Spacer. Scrap.”

The cattle guard covered a shallow concrete pit. Inside lay a length of chain, two beer cans, a snakeskin, and an old ceramic fuse.

Ace shone his lamp along the walls. Initials had been scratched into the concrete by generations of workers. One cluster spelled EL, but the letters were beneath a date from 1983.

“Elias would have been a child,” AJ said.

“A very committed child,” Pigsty said. “Building secret infrastructure before algebra.”

Hiro called from the irrigation line. He and Bron had uncovered a row of concrete inspection boxes running east from the compound. Most contained valves filled with soil. The fifth was clean.

“How clean?” Hayes asked. Bron pointed to a spiderweb across the lid.

“Clean inside. Undisturbed outside.” They lifted the cover. A circular brass plate occupied the bottom. Nine shallow holes ringed its edge. Pigsty looked around the group.

“Nine men. Nine holes. We are either chosen or hardware has been standardized.”

Hiro inserted the double-pointed pencil into one hole. It fit, but so did Code’s drift pin and the stem of a dry grass stalk.

“Not keys,” Hiro said. “Index positions.”

Code pressed the plate. It rotated freely and returned to its starting point under spring tension.

“A selector,” he said.

“For what?” Bron asked. The old irrigation pipe beneath them ticked once. Then, far down the line, another pipe ticked back. They spent twenty minutes proving the ticking was not a message.

Code rotated the plate through each of its nine positions while Carl timed the return between sounds. AJ changed the pressure on the spring. Hiro blocked sections of pipe with packed cloth. Hayes walked the line and marked where the sound weakened. Pigsty lay in the grass with his coat under his head.

“Useful?” Bron asked.

“Extremely. I’ve proven the stars are still present.”

“Any of them Elias?” Bron smirked.

“One looks judgmental, so possibly ARGUS,” said Pigsty.

The ticks came from thermal contraction in exposed pipe, not from the plate. The discovery pleased Tanner more than it annoyed him.