"That was a disrupter." He pointed at the Onzarian cruiser. "Our visitor is playing for keeps." His knuckles went white as he pulled back on the wheel into another long climb with emergency power. Another disrupter burst behind them barely missed. "They've got everything on us," he said. "Speed, firepower and range. Except maneuverability." He turned to Astrid. "Just how far out is the force screen from the house?" "Four hundred meters." "Let's see if we can judge it," he said grimly. "It's going to be close." He put the jet into a tight turn and slipped off into a steep, screaming dive. There was another disrupter burst and a sudden flutter of the controls. He fought them to maintain the dive, straight for the house and its invisible bubble of force. The flutter became worse as their speed increased, and vibration racked the whole ship. He judged the distance by the range-finder on the Baring. At the last moment he pulled out and up. The ship skidded down sickeningly, and then caught. Thane fought bitterly to keep conscious. They heard the explosion above the sound of the wind shrieking past them. Thane looked down and back. It had worked! The Onzar ship had followed them down, but it had not allowed for the invisible force screen. It had hit the screen, caromed off into a wild, twisting skid, and hit the ground, completely wrecked. But Thane had time only for a glance. The vibration was getting worse. One more strain and the little jet would be torn to pieces. He eased out of the climb and tried to put the jet into a long flat glide. It kept slipping off to the right, and the glide increased in steepness. The ground came up and he managed to pull back into a partial stall. At the last instant the jet dipped to the right and hit. It spun crazily on the ground, straightened, skidded and then buried itself in a drift of snow. He was still numb with shock when he heard Astrid's voice. "What happened, Roger? Why did they attack us?" "They must have been sent as soon as our force screen was detected. Let's get back." They climbed out into the biting wind and started towards the house in the distance. The red sun of Onzar was setting and the cold deepened and chilled bitterly as they hurried on. * * * * *