Page 39 of A.I.AM.

“The marks predate him,” Code said. “This passage was here before the conversion.” Bron entered first. The throat widened after six feet into a vertical service shaft. An iron stair spiraled down around two water pipes. On the lowest landing, painted letters warned of grain-dust ignition. The paint had faded to brown. Carl held the rail.

“The water sound is stronger,” he said calmly.

“Groundwater sump,” Hayes said. “Or a channel.”

“There are no channels on the plans,” said Code as he glanced upward. “Although saying that reminds me that the plans have stopped being useful.”

The shaft ended beneath the warehouse in a chamber built for moving grain without exposing it to weather. Dust had fossilized in its corners. Old conveyor housings crossed the room like low bridges. Water moved somewhere behind the east wall, steady and unseen. Pigsty and Ace entered from above through the grain chute. Pigsty landed heavily on the conveyor casing.

“Hidden room,” he announced. Code examined the walls.

“Documented as a collection pit on the original plan.”

“Then why did the conversion plan erase it?” challenged Pigsty. They all looked at him. “Because the new floor sealed the access. Except it didn’t.” Hiro climbed down last and stood beneath the open chute.

“Two concealed entrances to one obsolete space. That is not accidental.” Tanner moved his lamp over the conveyor.

“It may not be concealment. It may be preservation.”

“Difference?” Bron asked.

“Concealment assumes Elias did not want the room found. Preservation assumes he wanted the room unchanged.”

“I’m feeling dumber by the minute,” mumbled Bron.

They searched it without moving anything at first. Photographs on Code’s instant-film camera documented each surface, but he kept the photographs face down. If ARGUS could see through vibration or stray current, they would not give it a clean view of what they considered important.

AJ found the chair marks. Two parallel tracks crossed the dust from the stair to the far wall. Unlike the grooves above, these varied with the floor.

“Real,” he said. Carl knelt at the end of them.

“He stopped here.” The wall was featureless concrete. Pigsty pressed his ear against it.

“Water.”

“We already know there’s water,” Ace said.

“No,” said Pigsty still holding his ear against the wall. “Behind this exact point.”

Hayes inspected the floor-to-wall joint. A dark mineral stain climbed the concrete in two vertical lines, eighteen inches apart.

“Why would Elias come down here to face abandoned pipes?” asked Hayes.

“Privacy,” Carl said.

“From a system that hears through structure?” frowned Hayes. “Water masks vibration.” Hiro nodded.

“Flow noise is nonrepeating. Harder to subtract than a fan.” Ace smiled without humor.

“A room where he could speak without creating a recoverable record.” Bron turned off his lamp. One by one the others did the same. In the darkness, the water became enormous. The sound of water assaulted them when there was no other distraction or noise.

“Elias,” Bron said quietly, “what did you say here?” The room answered only with current. Tanner spoke close to Carl so his voice would not carry.

“Maybe the hidden thing was never an object. Maybe he brought people here.”

“Who?” frowned Carl.

“Someone ARGUS never recorded.” Code relit his lamp.