"My brother and I have some hand grenades," Diego said, reach- ing over to tap his backpack. "Three apiece. Enough?"

In answer, Ryan glanced at Mercer, who said, "It could work if they're positioned in the right place."

"What can I do?" said Therri, who had been listening to the dis- cussion.

"Ben's people are in pretty tough shape," Ryan said. "They'll need your help, especially the kids."

"I'll do my best," Therri said. She kissed him and gave Mercer and Ben a peck on the cheek as well. "Take care of yourselves."

As Therri made her way back into the forest, Ben and the other men pushed the catamaran off the beach and climbed aboard. The boat's twin hulls and powerful motors gave it a respectable speed. They scudded over the surface of the lake and soon reached the op- posite shore. Pablo and Diego rode shotgun in the bow as the boat coasted up to the pier. They quickly tied up and headed inland.

Mercer made a stop at the boat shed and emerged with two reels of three-eighths docking line, some cord and a roll of duct tape. Walking single file, they detoured around the plaza. With Ryan in the lead, the group made its way undetected to the side of the dome.

Ryan found what he was looking for: a tall, cylindrical fuel tank lo- cated in a clearing surrounded by dense woods. Painted on the side was a warning that the tank contained highly flammable contents. A steel pipe about six inches in diameter ran from the tank to the side of the building. Next to where the pipe entered the airship hangar was a locked door. Like the dome itself, the door was made of a plas- tic material and easily gave way to the strength and determination be- hind Diego's shoulders.

Then he and the others stepped into a short passageway that ran parallel to the pipe for several yards. The conduit disappeared through a wall next to another door, this one unlocked. Ryan took the lead and opened the door a crack, giving him a view of the inte- rior of the airship hangar. Men milled around in the middle of the building, where the airship had been tied down. Others were coiling lines or moving gantries and scaffolding. A few guards were drift- ing out the hangar's main door.

Ryan motioned for the others to stay put while he and Mercer stepped into the hangar. They crawled along the wall behind tall stacks of coiled hose until they came to where the pipe entered the building. Barker had gestured toward the hose when he had ex- plained why he used hydrogen rather than helium to fill the airship's gasbags. A valve controlled by a large hand-turned wheel allowed the flow of gas into the hose. Ryan turned the wheel on the pipe until they could hear the hiss of gas escaping through the nozzle.

The escaping gas rose to the roof, where it wouldn't be detected, they hoped, until it was too late. With their work done, they slipped out the door and followed the passageway into the open. Ben and Diego had been equally busy. Following Mercer's instructions, they had taped the hand grenades onto the tank. Short lengths of cord had been attached to the safety-pin rings and ganged to the line from one of the spools. Ryan and Mercer inspected the work, found it satis- factory, then walked back to the lake, uncoiling the line behind them. They tried to run the line straight back to the lake, keeping it clear of bushes and trees where it could snag.

When they'd emptied one two-hundred-foot-long spool, they spliced the free end onto another spool. They were still a dozen yards short of the lake when that spool gave out, too. Mercer ducked into the boat shed and came out with several lengths and sizes of rope that they spliced together until the rope reached to the water's edge. When all was ready, Diego headed back to the plaza and took a position be- hind a thick tree.

With their work inside the hangar done, Kiolyan men were streaming out into the plaza, some of them heading in the direction of their barracks. The Basque coldly took a bead on a guard and let off a short burst. The man fell to the ground. More guards came running from the direction of the barracks and began to fire indis- criminately into the woods where they saw muzzle flashes, but Diego moved after each kill and the bullets went far wide of their targets. When two more of their number were killed, the men in the plaza ran for the door of the giant igloo.

Diego had counted on exactly this reaction. He had tried to pick off the men who were making a break for the woods. The effect was to herd the guards into the "protection" of the structure. He knew that, given time, they would emerge from other exits in the dome and fan out into the woods and try a flanking maneuver. But as the last man disappeared into the airship hangar, leaving the plaza deserted, Diego was already sprinting back to the beach.

Waiting on shore, where he and the others had been alerted by the sound of gunfire, Ryan saw Diego running toward him and handed the end of the line to Ben.

"Would you like to do the honors?"

"Thanks," Ben said, taking the line. "Nothing would give me more pleasure."

Ryan turned to the other men. "When Ben yanks on that line, dive into the water and keep your head under for as long as you can. Okay, Ben. Let'er rip!"

Ben jerked hard on the line, then dropped it and dove with the others into the lake. They filled their lungs with air, then ducked below the surface. Nothing happened. Ryan poked his head out and swore. He sloshed out of the lake onto the beach, picked up the loose end of the line and gave it a tug. It tugged back as if caught on a branch.

"I'll check. Must be hung up on something," he called out to the others, and followed the line inland.

Ryan was only partly right. The line was snagged on someone, not something. A stray guard had seen Diego bolt for the lake and had gone over to investigate. He was holding the line in his hand when he saw Ryan approach from the beach. Ryan was bent low, his eyes following the line, and he never saw the man level his gun. The first sign that he was not alone was the impact of the bullet hitting him in the shoulder like a fiery hammer blow. He dropped to his knees.

The guard never got off another shot. Diego, who had been fol- lowing Ryan's trail, let off a burst that stitched its way across the guard's chest. The guard was thrown back by the impact, but his fingers clutched the line in a death grip. Ryan watched through filmy eyes as the guard fell, his weight pulling on the line. An alarm sounded in his brain, cutting through the pain and confusion, and he tried to rise, but his legs were made of rubber. Then he felt strong hands lifting him to his feet and guiding him back toward the lake. They were almost at the water's edge, when the lake lit up as if it had been sprayed with phosphorescent paint.

When the guard had toppled over, the tug had been transmitted along the line to the grenade rings. They'd popped out, and the levers had gone flying, igniting the fuse train. Six seconds later, the grenades went off simultaneously. A millisecond after that, the hydrogen in the tank ignited. The fiery gas rushed along the short length of the pipe and exited through the nozzle as if it were expelled from the busi- ness end of a flamethrower. The spurting flames touched off the in- visible cloud of hydrogen hanging under the dome.

The airship hangar became a hell for the Kiolyan guards. Satu- rated with hydrogen, the superheated air exploded inside the dome, instantly incinerating flesh and bone. The dome contained the heat for only a few seconds, glowing white hot, before the thick plastic cells that formed the walls evaporated. But the delay before the final explosion of flames gave Ryan and Diego the time they needed. They gained the water's edge and dove into the lake as the dome exploded and sent out sheets of flame that vaporized the surrounding forest and outbuildings. Blistering waves of heat rippled out in every di- rection.