"Or perhaps there are living creatures on them," Jan muttered. Karin said, "It's beginning to seem possible. And I'm afraid that if we stay here long enough, we'll find out." "I'm afraid so too," Jan conceded. "We both wanted living companions--but not unknown shapes of fire." Seventeen hours after the end of the corona explosions, they noticed activity on the yellow star. What took place resembled the formation of sunspots, but the eruptions were like none they had ever seen. As they grew, they darkened, and began to rotate with increasing speed, so that soon the surface of the yellow star was covered with black, whirling specks. The specks drew together, and then shot out abruptly toward the green star. Once more Jan acted. As the black objects raced toward him, he sent the ship full speed ahead to get out of their way, and as he did so the now elongated spheres of spinning blackness sailed straight past the ports. They were in the vacuum of space, but even so Jan noted that the ship rocked as if battered by the waves of an ocean. From the green star came answering black objects, which grew like sinister soap bubbles. The bubbles caught the attacking spheres, and wherever defenders and attackers made contact, a blinding flash of light was followed by a quick burst of high-energy radiation. "Rule out natural forces," said Jan decisively. Karin nodded. "Each star is either alive, or has living things on it. They're fighting a war." She repeated the word. "A _war_. It seems incredible--terrifying." "I'm afraid you've forgotten our own past. Haven't you studied your history? We had wars once too." "But so long ago, Jan! It seems impossible to believe that half the human race ever tried to destroy the other half." "Well, they didn't succeed. There's no use moralizing. Now, at least, we have something pretty definite to go on. When the creatures of one star launched a force field, those of the other star defended themselves with a force field of their own. Directly between the stars, the fields balance pretty well, permitting us to move. But toward the rim of the region where they collide, the forces work in the same direction, and keep us from breaking free." "Now that we know that--what can we do?" "Nothing, I'm afraid," admitted Jan. "Neither star will relax its field for fear of falling victim to the other. That leaves us in the middle, exactly as before." He said thoughtfully, "Karin, did I ever tell you of that ancient history book I once saw? It actually depicted our barbaric ancestors on a battlefield? There were long rows of trenches on either side, apparently as a protection from the primitive missiles they were capable of launching. And sitting on the blackened limb of a tree that had been shot almost to bits, in what was called 'No Man's Land', sat a bird.