It was the final proof. Duncan was the first man who had ever landed on Pluto. The Varra intended to destroy him, giving him no opportunity of telling what he knew to Earth. Duncan checked the radio. It was repeating his message, sending it steadily into space. At this distance from the Sun there was no chance that it would be picked up. But later— He clicked the power on in his Helmet. There was no response. The Varra, as he had thought, could not penetrate his artificial barrier, his pseudo-Heaviside Layer. It was nothing, actually, but a blanket of ionization. But the Varra could not break through it. Duncan glanced at the exposed radium on the floor. A pound of it, sending out its powerful emanations, gamma, beta and electrons, ionizing the chlorine even more effectively than it would have affected oxygen—invisible armor, protecting Duncan from the Varra. They were massing ahead, determined to stop him. Thoughts began to penetrate his mind, furtive, random, but indications that the group power of the Varra was stronger than he had expected. Duncan seated himself at a panel, the one controlling the blaster cannons. His face, haggard and strained, twisted in a bitter smile. “Okay, Andrea,” he whispered. “I’m taking the message back for you. But I’m doing this—for myself! Because they killed you, damn them—” The chill tentacles probed deeper into Duncan’s brain. He swung a cannon into position, pressed a stud, and watched a streak of electronic energy go blasting across space, silent thunder in the void, smashing relentlessly at the Varra. It struck in a maelstrom of flame. “Vulnerable!” Duncan said, “Yeah, they’re vulnerable as all hell!” The Varra closed in. Through their massed ranks the cannon blazed and pounded, till space seemed afire. The rocking recoil of the blasts, mingled with the booming of the rockets, thudded in Duncan’s ears even through the Helmet. And he fought them. There were no witnesses to that battle, none to see the black cruiser plunging on through the cloud of attackers, belching Jove’s lightning, shaking with the vibrations of its murder-madness. For the spaceship was mad, Duncan thought, a relentless, destroying avenger, a dark angel bringing the terror of Armageddon to the Varra. And the energy-beings never paused; their life and their future was in the scales. If Duncan broke through, they were doomed. He must be stopped. * * * * * They could not stop him! Almost blind with the agony burning within his brain, Saul Duncan nevertheless hunched over the controls, while the cannons thundered their demoniac message into space. By dozens and hundreds the Varra died, their energy-matrices wrenched and broken by the electronic bolts. Duncan and the ship were one—and both were mad. He got through. He had to. Nothing could have stopped Saul Duncan, not even the Varra. In the end, the black cruiser raced Sunward, cannons silent, for the Varra were scattered.