Simms leaped into the cabin and fumbled for the starter switch. Once a dozen years before he had driven a hydrocar on a pleasure cruise a short distance up the Martian Central Canal. Now his fingers touched the stud, and the motor roared into life. But before he could press the trigger out into the swamp, he saw Halleck leap through the water and hurl himself onto the car's hood. The man broke the windscreen into a hundred glass fragments and thrust a mold gun through the aperture straight into Simms' face. But before he could press the trigger something happened. Back in Xenthar village a mighty wailing scream pierced the air. Like a frightened banshee the sound raced into the upper register, leaped to a grinding, ear-shattering shriek. Halleck dropped the mold gun and clapped his hands to his ears. On shore the Kamalis uttered cries of pain and fell groveling as the sound mounted into the supersonic range and the piezo-electric crystals began their action. With a jerk Simms swung the wheel, throwing Halleck off balance and plummeting him into the water. The hydrocar roared out into the swamp like a runaway comet. * * * * * All night Simms drove, weaving through aisles of man-high rip grass, circling denser groves of blue priest trees and ardaleptic ferns. At dawn he drew up at a small island, built a fire and cooked some of the food he found packed away in a rear compartment of the hydrocar. He rested half an hour, reentered the car and drove on at a more leisurely speed. There remained now only to go to GHQ at BeTaba, give his report and hand over his message-cylinder. And when the tube was opened, he would be through on Venus. Dismissed from the Service for insubordination. Wherever he went, that report would follow him. His lips compressed. There was a girl waiting for him back on Earth--waiting until he had completed his hitch in the Service and could graduate to the spaceways. Abruptly his hand, reaching to his belt, stopped, and an electric shock ran through him. His message cylinder was gone! He must have lost it when he rested at the little island. For a moment he sat motionless, a cold numbness sweeping over him. He must have that cylinder when he reported at BeTaba. That part of the message pertaining to reenforcements for the garrison would be given orally, of course. But the section regarding himself was different. If he failed to deliver that letter, sooner or later he would be accused of throwing it away. It would mean another case of--insubordination. Suddenly he threw over the wheel and sent the hydrocar racing back in the direction from which it had just come. The Great Swamp faded out of his vision now. He drove with his thoughts. And then as familiar landmarks began to rise up before him, he realized what he was doing.