"Marte!" His voice echoed hollowly, dying away to an eerie whisper, fainter and fainter. It was very silent here on the last level below the giant atomic motors. The feeble light showered down from a single overhead bulb; it was their special bulb. Marte always lit it when she came below. "Marte!" His voice was almost pleading. "Here I am, Johnny. Over here." "Little imp," he said, not unkindly. "What do you mean, hiding?" "Hiding, Johnny? I wasn't hiding.... And besides, you looked so funny and