He descended the ring, half climbing, half falling. He almost shouted in exultation when he came upon the third transverse pas- sageway. He ran down the corridor, pausing at each ring to listen. He was guessing that Scarface would make his way as far forward as he could before descending to the control car using another ring.

At the third juncture of a keel and a ring, Zavala heard a ting-ting as someone climbed down the metal ladder. He waited patiently until he could hear heavy breathing. He flicked on the light. The beam caught Scarface clinging to the ladder like a large, ugly spider. Scarface saw that he'd been intercepted and began to climb up the ladder.

“Hold it right there!” Zavala ordered. He brought the shotgun to his shoulder.

Umealiq halted and looked down at Zavala with an ugly leer on his face. “Fool!” he shouted. “Go ahead and fire. You'll be signing your death warrant. If you miss me and hit a hydrogen bag, the air- ship will go up in flames and you and your partner will die.”

Zavala's lips twitched at the ends. As an engineer, he was well- acquainted with the properties of various elements. He knew that hy- drogen was volatile, but unless he was using a tracer bullet, combustion was unlikely. “That's where you're wrong,” he said. “I'd just end up punching a hole in the gas bag.”

The evil smile vanished. Umealiq bent off the ladder and pointed his gun at Zavala. The shotgun boomed once. The heavy shell hit Umealiq squarely in his broad chest and knocked him off the ladder. Zavala stepped back to avoid the body that crashed to his feet. As his life ebbed, Umealiq's face was twisted in disbelief.

“That's something else you were wrong about,” Zavala said. “I don't miss.”

While Zavala was chasing Scarface, Austin had been fighting for his life. Again, he had thrown his left hand up so that the edge of it caught Barker's wrist and stopped the descending knife inches from his neck. With his right hand, he reached up to grab Barker by the throat, but the other man jerked back. Austin's groping fingers yanked off the sunglasses. He found himself staring into Barker's pale-gray snake-eyes. Austin froze for a second and lost his grip on the wrist. Barker jerked his arm back, prepared to make another thrust.