The ship. The grunting roar had come from the Kruchek drivers fighting the gravity of the planet.
The ship had taken off without them.
Had Nielson gone mad? Had he seen danger approaching and jumped the ship into the sky to escape it?
"Wait! Nielson! Pick us up!"
The ship flew on. Gaining speed, it passed over their heads. They caught another glimpse of it as it passed over an opening in the branches of the trees. Then it was gone, the throb of the drivers dying quickly away.
"Nielson will come back for us." Noble's voice, usually poised and assured, was garbled. "He'll return and pick us up. He won't leave us here."
"He had some reason for taking off," Hargraves heard himself saying. "He'll come back. He has to." Subconsciously he knew that this, at the very best, was wishful thinking.
The ship had no more than vanished until another sound came to their ears, that of men shouting. A group came into sight among the trees, following along the ground the course the ship had taken through the air.
"They're our fellows!" Hargraves heard Noble gasp.