"The guards are lazy," Giordino replied. "They loosed the dogs to run by themselves."

"A wonder they haven't scented us by now."

"You spoke too soon. I see three of them staring in our direction. Oh, oh, here they come on the run."

Before the dogs began barking, Pitt reached into the knapsack on his back, grabbed the steaks from the restaurant and heaved them onto a ramp leading to the nearest bastion. They landed with a distinct plop sound that the dogs heard and homed in on.

"Are you sure this will work?" Giordino murmured.

"It always does in the movies."

"Now there's cheery assurance," Giordino groaned.

Pitt dropped down off the tree limb to the ground and stayed on his feet. Giordino followed, casting a wary eye on the dogs, who chewed their raw meat in happy delirium without paying the least attention to the two intruders.

"I may never doubt you again," Giordino said under his breath.

"I won't forget you said that."

Pitt led the way toward one of the stone ramps, using the night-scope to see when the nearest TV camera swung to its widest arc. When he signaled with a whistle, Giordino ran under the camera's blind side and sprayed the lens with black paint. Moving on, they paused outside the closed and darkened museum, listening for suspicious sounds. Muted voices could be heard over the ramparts inside the main courtyard, where the guards' temporary barracks had been constructed. They entered what was once a storeroom. The stonewalls were still solid, but the wooden beams and roof were long gone.

Pitt motioned toward a central turret that rose above the rest of the fort. It was built like a pyramid with the upper half sliced off at the middle. "If there is a vertical ventilator shaft from below, it has to come out there," he said softly.

"The only logical place," Giordino agreed. Then he cocked an ear. "What's that racket?"

Pitt paused, listening, his senses alert, his ears piercing the night. Then he nodded in the darkness. "That whirring sound must be coming from the ventilator fans."

Keeping in the darkened shadows, they climbed a narrow ramp of stones that protruded from the walls of the turret and ended at a small access door. A rush of cool air through the narrow opening struck them with nearly the force of a wind tunnel. Bending low against the draft, Pitt entered and found himself standing at the base of a large wire-mesh cage. The whirring noise from the fan blades beating the air below the mesh opening magnified and tore at their eardrums.

"Noisy devil," yelled Giordino.

"That's because we're right on top of it. Be a lot worse if it didn't have silencers installed. As it is, the noise is pretty well muted outside the turret."

"I didn't bargain for a gale-force wind," said Giordino, as he examined the thickness of the wire-mesh cover.

"The fans are designed to produce a computer-calculated volume of air at an efficient pressure."

"There you go again with the lecture. Don't tell me you took a basic course in tunnel construction."

"Have you forgotten the summer between semesters at the Air Force Academy when I worked in a silver mine in Leadville, Colorado?" retorted Pitt.

"I remember," said Giordino, smiling. "I spent my summer as a lifeguard in Malibu." Giordino peered through the wire mesh. A glow of light rose from the opening. He walked around the mesh until he found a bolt holding it to a latch. "Locked from the inside," he observed. "We'll need to cut through the mesh."

Pitt produced a small pair of wire cutters from his backpack. "I thought we might need these if we ran into barbwire."

Giordino held them up to the light from below. "They should do nicely. Now please stand back while the master creates an entrance."

It looked easy, but wasn't. Giordino was sweating rivers twenty-five minutes later when he finally cut a hole high and wide enough for them to crawl through. He handed the cutters back to Pitt, pulled the mesh apart and peered into the shaft. The square-cut ventilator shaft, acting as the passage for the expelled air from the tunnel far below, was fifteen feet wide. A circular metal tube filled one corner. This was the access shaft, with a ladder that seemed to vanish into a bottomless pit.

"For maintenance in case the ventilator system needs repair," Pitt volunteered loudly over the fan noise. "It also serves as an emergency exit for the mine workers should there be a fire or a roof collapse in the main tunnel."

Giordino entered the shaft feet first onto the lower rungs of the ladder. He paused and looked up at Pitt sourly. "I hope I won't regret this!" he shouted over the roar of the fans, as he began his descent.

Pitt was thankful the shaft was lit. After dropping down the ladder fifty feet, he paused and looked below. All he could see was the ladder stretching into infinity, like the tracks of a railroad. No sign of the bottom was visible.

He pulled out a paper towel from a pocket, tore it into two small pieces, wadded them up and stuffed them in his ears as plugs against the irritating noise level of the fans. Besides the main fan system, booster fans had been installed every hundred feet to maintain the required pressure to vent the tunnel to the surface.

After what seemed half a lifetime, and what Giordino estimated was a drop of five hundred feet, he stopped his descent and waved a hand. The bottom of the ladder was in view. Slowly, cautiously, he turned until he was upside-down. Then he crawled downward until his eyes could see under what was now the roof of a small control center that monitored and detected the gasses, carbon monoxide, temperature and fan system operations.

Pitt and Giordino had passed far below the main fan system and could now converse in low tones. Giordino raised up until he was on his feet again and spoke to Pitt, who had slid down the ladder beside him.

"What's the status?" Pitt asked softly.

"The ladder runs through a ventilator systems control center that sits about fifteen feet above the floor of the tunnel. A man and a woman are sitting at computer consoles. Luckily, they're facing away, with their backs to the ladder. We should be able to take them out before they know what hit them."

Pitt looked into Giordino's dark eyes, only inches away. "How do you want it?"

Giordino's lips parted in a conniving grin. "I'll take the man. You're better at incapacitating women than I am."

Pitt glared at him. "You big chicken."

They wasted no more time and dropped down the ladder into the control booth silently without being detected. The system operators — the man wearing black coveralls, the woman in white — were intent on monitoring their computers and did not see the reflection of their assailants in their screens until it was too late. Giordino came in from the side and slugged the man with a right hook to the jaw. Pitt opted for striking the back of the woman's neck just below her skull. Both went out with no more than slight moans.

Keeping unseen below the windows, Pitt pulled a roll of duct tape from his knapsack and tossed it to Giordino. "Bind them up while I remove their coveralls."

In less than three minutes the unconscious ventilation systems operators were bound and gagged in their underwear and rolled under counters out of sight from anyone passing by below. Pitt slipped on the black coveralls, which were a loose fit, while Giordino burst the seams of the white coveralls that came off the woman. They found matching hard hats on a shelf and put them on. Pitt casually carried his knapsack over one shoulder, while Giordino looked official with a clipboard and pencil. One after the other, they dropped down the ladder to the tunnel floor.