Without realizing it, he acquired a new purpose, a duty as compelling as that of any soldier or fire-watcher. He had to keep that trembling body of his alive, mount to the tall rust tower overhead. He climbed and he made Ida climb, till, at nightmare's end, the fog thinned and they came into clear, windswept air and clawed up the last hundred feet to sanctuary. They were completely spent. Without word or thought they crept within the tower, huddled together for warmth on its dank steel deck, and slept for several hours. * * * * * Roddie awoke as Ida finished struggling free of his unconscious grip. Limping, he joined her painful walk around the tower. From its openings they looked out on a strange and isolated world. To the north, where Ida seemed drawn as though by instinct, Mount Tamalpais reared its brushy head, a looming island above a billowy white sea of fog. To the south were the Twin Peaks, a pair of buttons on a cotton sheet. Eastward lay Mount Diablo, bald and brooding, tallest of the peaks and most forbidding. But westward over the ocean lay the land of gold--of all the kinds of gold there are, from brightest yellow to deepest orange. Only a small portion of the setting sun glared above the fog-bank; the rest seemed to have been broken off and smeared around by a child in love with its color. Fascinated, Roddie stared for minutes, but turned when Ida showed no interest. She was intent on the tower itself. Following her eyes, Roddie saw his duty made suddenly clear. Easy to make out even in the fading light was the route by which Invaders could cross to the foot of this tower on the remaining ruins of the road, climb to where he now stood, and then descend the cable over the bridge's gap and catch the city unaware. Easy to estimate was the advantage of even this perilous route over things that scattered on the water and prevented a landing in strength. Easy to see was the need to kill Ida before she carried home this knowledge. Roddie took the hammer from his waist. "Don't! Oh, don't!" Ida screamed. She burst into tears and covered her face with scratched and bloodied hands. Surprised, Roddie withheld the blow. He had wept, as a child, and, weeping, had for the first time learned he differed from his friends. Ida's tears disturbed him, bringing unhappy memories. "Why should you cry?" he asked comfortingly. "You know your people will come back to avenge you and will destroy my friends." "But--but my people are your people, too," Ida wailed. "It's so senseless, now, after all our struggle to escape. Don't you see? Your friends are only machines, built by our ancestors. We are Men--and the city is ours, not theirs!"