Carr Parker sat day-dreaming at the Nomad's controls. More than a week of Earth time had passed since the self-styled "vagabonds of space" had left Europa, and now they were fast approaching the great ringed orb of Saturn with the intention of exploring her satellites.

Behind him, his Martian friend, Mado, was manipulating the mechanism of the rulden, that remarkable Europan optical instrument which Detis had installed in the vessel before they left. Mado was utterly fascinated by the machine, having spent most of his time during the voyage searching the surfaces of Saturn's moons for signs of human habitation. Now, as they headed directly for Titan, the sixth satellite, he was completely absorbed in an examination of the heavy cloud layer that covered it.

But Carr's thoughts were of his bride, who still slumbered in their stateroom amidships. In his bachelor days he never had imagined he could find such contentment as had come with his marriage to Ora. He had fought shy of the fair sex on Earth. Somehow, the women he knew back home had bored him; angling for a man's money and position, most of them, and incapable of giving real love and companionship in return for the luxuries they demanded. He was resigned to his single state.

But all that was changed by the little blue-eyed girl he had met in Paladar. She was a different sort; worth a hundred of those others and fulfilling to perfection the ideal he had always set up. On her world, Jupiter's satellite, Europa, he had neither wealth nor influence; he'd left these behind when he deserted Earth for a life of vagabondage among the stars. But, to the daughter of Detis, this lack meant less than nothing; his love, and hers, meant everything.

And, what a good sport she had been! When they were threatened by Rapaju and his minions; when they barely escaped being swallowed up by that monster of space which Mado had likened to the Sargasso Sea of Earth; when she herself proposed joining them in their rovings throughout the universe.

She was a companion of whom even the phlegmatic Martian was proud, she brought with her presence on the Nomad a subtle something that made of the coldly mechanical space-ship a thing of new beauty and a place of cheerfulness-a home. And, to think he had won her for his own. To think....

"Carr!" Mado's sharp exclamation startled him from his pleasant thoughts. "Come here and take a look at this," the Martian demanded, his voice betraying an excitement unusual for him. "Something is wrong on this satellite we're heading for."

Locking the controls in the automatic position, Carr turned to join his friend at the viewing-disk of the rulden. Mado had found an opening in the heavy cloud layer, and before them was an unobstructed view of a rugged countryside where huge boulders had been scattered by the mighty hand of creation and where the sun shone weakly on the rim of a yawning crater in which sulphurous vapors curled. They saw this strange land as from an altitude of a few hundred feet, though the Nomad was still more than a million miles from the satellite.

"What's wrong about that?" Carr grunted. "Excepting that it's just another of these barren and useless bodies that doesn't even provide us with an attracting interest."

"Wait," Mado replied, "You'll see in a moment. Something-"