The train slowed and slid with a faint humming noise over an elevated platform. Two men in black jumpsuits ran next to the cars as they came to a stop. Lanier stood and she followed him to the door. It opened as silently as before.

Forest, water, dirt—all in one glorious sniff.

"Later, Charlie," Lanier said. Charlie saluted smartly and took a stance in the doorway behind them.

A platform guard stepped up to examine Patricia's badge. "Welcome to summer camp, Miss Vasquez," he said. She looked down from the platform railing. They were six meters above the ground. The platform was surrounded by a compound much like the one in the first chamber, with fiberboard buildings and earthen ramparts, but a much larger greenhouse-agriculture laboratory.

Everyone in the compound wore black, in combinations of black and khaki, black and green, and one black and gray. "Security forces?" she asked. Lanier nodded as they descended the platform stairs.

"We keep a small science group here, and we let people take their vacations or liberty here, when there's time for such things, which isn't often. This chamber is strategic. It divides the relatively livable parts of the Stone from the business end."

"The propulsion system?"

"That, and the seventh chamber. Anyway, you'll have a chance to stretch your legs, assimilate what you've seen so far."

"I doubt it," Patricia said.

Lanier guided her to the compound cafeteria.

In most respects, the cafeteria was little different from the one in the first chamber. They sat at a table with British and West German soldiers. Lanier introduced her to the German commanding officer, Colonel Heinrich Berenson. "He'll assume command of the seventh chamber security forces a week from now. You'll be working together quite a bit."

Berenson was a colonel in the West German Space Force, sandy-haired and freckle-faced, as tall as Lanier but more obviously muscular. He appeared more Irish than German; with his non-German name and sophisticated manner, he seemed truly international to Patricia. His manner was friendly but slightly distant.

She ordered a salad—fresh greens from the agrilab—and looked at the faces of the men and women around her. Not all of them had green badges.

"How does the badge system work?" she asked Lanier. Berenson smiled and shook his head, as if this was a sore point.

"Red badges are confined to the bore hole in the first chamber," Lanier said. "Mostly engineering support. Blue can go anywhere in the Stone except the sixth and seventh chambers, but in all chambers but the first, must be escorted and must be performing specific duties. Green badges can go to any of the chambers but are always subject to security checks."

"I am here more than three years," Berenson said, "and I only get a green three months ago." He glanced down at her badge and nodded meaningfully. "Fortunately, I found a loophole. I can be considered to have escorted myself."

Lanier grinned. "Let's just be thankful things are going as smoothly as they have been."