The road curved south and the darkly bronzed moon came swinging out over the Pacific as it rode along with them.

“Now, wait a minute, Margo,” Paul protested, lifting his left hand for a moment from the wheel. “I got the same idea myself, so I asked Van Bruster about it He says it’s completely unlikely that one single field, traveling through space, was responsible for the four twists. He thinks there were four different twist fields involved, not connected in any way — so there can’t be any question of something creeping up on the moon. What’s more, he says he’s not too surprised at the photos. He says astronomers have known the theoretical possibility of such fields for years, and that evidence for them is beginning to show up now, not by chance, but because of the electronically amplified ’scopes and superfast photographic emulsions that have just gone into use this year. The twists show up in star snapshots where they wouldn’t in long exposures.”

“What did Morton Opperly think of the photos?” Margo asked.

“He didn’t…No, wait, he was the one who insisted on plotting the course of the twist fields from Pluto to the moon. Say, we just passed Monica Mountainway! That’s the fancy new road across the mountains to Vandenberg Three where Opperly is right now.”

“Was the Pluto-moon course a straight one?” Margo asked, refusing to be deflected.

“No, the darndest zig-zag imaginable.”

“But did Opperly say anything?” Margo insisted.

Paul hesitated, then said, “Oh, he chuckled, and said something like, ‘Well, if Earth or Moon is their target, they’re getting closer with each shot.’ ”

“You see?” Margo said with satisfaction. “You see? Whatever it is, it’s aiming at planets!”

Barbara Katz, self-styled Girl Adventurer and long-time science-fiction fan, faded back across the lawn, away from the street-globes and the Palm Beach policeman’s flashlight, and slipped behind the thick jagged bole of a cabbage palmetto before the cold bright beam swung her way.