When the aides came to clean up Guy's office, they found him inspecting the little instrument that fitted head and waistline of the alien creature. It was off, now, and partly disassembled upon the patrol marshal's desk. Williamson came at Maynard's call and raised an eyebrow at Maynard's action. "I had to do something," said Guy in a flat voice. "I couldn't just sit here and contemplate those bodies." "I know," said Ben softly. "Anything I can do?" "Yes. Set up a barrier. Focus the screen's output on the center of Mephisto. And then maintain that barrier for your life--and it will be just that. It will be for your very life, for it will be against the lives of all Mephistans!" "Good!" glowed Williamson. "That'll do it!" "It may take months," said Maynard. "But from now on we're fighting a winning battle." "What is that thing you're tinkering with?" "A goldberg that was on the creature's body. Interesting thing, too. Look, Ben, this thing may have been a robot, but their psychology is such that they hate us completely. Issue orders that no more prisoners are to be taken. Extermination is the only way; their strength is such that three of them could wipe out a regiment. If we don't exterminate them, they'll exterminate us, and they can do it if we permit them one chance. We'll not give them that chance. Have the technicians figure out the estimated temperature rise of Mephisto with a full screen and full output directed at the center of the planet. I'd like to know when this affair can be considered over." "Check. I'll do it, Guy. What you need is a rest." "I know. But there'll be no rest for any of us until this fight is finished. Come on, Ben. Let's get moving. We've got a job to do." XII. Guy put the alien instrument in his personal locker and went to see how the battle was coming. Out across the face of Mephisto, he saw the battle machinery locked in mobile death with the huge, alien machines of Mephisto. The ground was strewn with smoking ruin, and Guy saw with horrified gratification that the ruined machinery was all on the Terran side of the battleground--which meant that his ring of offense was advancing. The energy bombs were bursting above the planethead, and the sky was filled with blinding light. Sub-ships fell as their drive was burned by the entrapped energy within the barriers, and Guy wondered how many men were getting energy burns from the terrific radiation from the energy bombs. _Orionad_, standing in the circle of planeted ships, was dealing power blows from the turrets, and beams of energy--just energy--were roving the sky to saturate the barrier-protected sub-ships. Now and then a MacMillan beam would touch one of the sub-ships unawares, and there would be a terrific blast as the entire ship exploded instantly. Then Guy saw his forces waver slightly, fall back, and then go down in a terrible wave of destruction from massed sub-ships.