Since the natives' intentions were obviously not hostile, retaliatory measures were out of the question. So the Earthmen spent the next few days in using some of the same rocks to build a large wall some distance away from the house, hoping that it would provide a still more attractive target. However, there were several scores of the creatures involved in the game by then and only part had their activities successfully diverted.
"Well, every little bit counts," Danny tried to soothe the angry Ned, who had been trying to show the natives that building with the rocks was more fun than throwing them and, for his pains, had received a stone in the solar plexus.
On their last mission, the two young men had been absorbed in mapping an interesting valley in the north polar regions—a pursuit which they had no intention of giving up. A few days after they had finished the work, therefore, they announced their intention of taking the helicopter out again. "And, remember, girls," Ned adjured them, "don't go out of the house at all until we come back."
"We need fresh air," Jane said.
"The air inside is a lot fresher than out," her husband retorted, "because it's purified. So, mind you, don't set foot out of the door until we return."
"Except in an emergency," Judy told him.
"Maybe we'd better leave the valley for later...." Danny murmured.
"Oh, come on!" Ned protested. He had been dragooned into washing the dishes several times during the weeks they'd spent at home building the wall for the natives, and had no intention of letting the same misfortune befall him again. "What kind of emergency could there be?"
"If Judy has her heart set on an emergency," Dan prophesied, as he allowed himself to be led off, "there'll be an emergency."