“There. That light. There it is again.”
Through a window in the end wall of the station blinked a light, once, twice, thrice. Then all was dark again.
“Signal,” said Jack with conviction. “Somebody’s up there.”
“Come on, let’s find out,” said the impetuous Frank, starting forward.
Jack restrained him.
“Better tell Ensign Warwick.”
Without a word, Bob turned and darted away up the trail. He was back in five or six minutes.
“Can’t see them,” he said, “they must have left the trail and struck off at an angle somewhere. I used my flashlight, too, but couldn’t see a soul.”
“Very well,” said Jack. “Then there’s nothing else for it. We can’t let that light go unchallenged. We’ll have to investigate ourselves. Come on.”
The three chums started picking their way among the loose stones, up the side of the hill, in the darkness.