They weren't where Bob and Queazy had calculated, as they had discovered the next day. They had expected to pick up the asteroid on their mass-detectors a few hundred thousand miles outside of the Moon's orbit. But now they saw the giant ship attached like a leech to the still bigger asteroid--inside the Moon's orbit! A mere two hundred thousand miles from Earth! "We have to work fast," Bob stammered, sweating. He got within naked-eye distance of the Saylor brothers' ship. Below, Earth was spread out, a huge crescent shape, part of the Eastern hemisphere vaguely visible through impeding clouds and atmosphere. The enemy ship was two miles distant, a black shadow occulting part of the brilliant sky. It was moving along a down-spiraling path toward Earth. Queazy's big hand gripped his shoulder. "Go to it, Bob!" Bob nodded grimly. He backed the hauler up about thirty miles, then sent it forward again, directly toward the Saylor brothers' ship at ten miles per second. And resting on the blunt nose of the ship was the "yo-yo." There was little doubt the Saylors' saw their approach. But, scornfully, they made no attempt to evade. There was no possible harm the oncoming ship could wreak. Or at least that was what they thought, for Bob brought the hauler's speed down to zero--and Starre Lowenthal's little ship, possessing its own inertia, kept on moving! It spun away from the hauler's blunt nose, paying out two rigid lengths of cable behind it as it unwound, hurled itself forward like a fantastic spinning cannon ball. "It's going to hit!" The excited cry came from Starre. But Bob swore. The dumbbell ship reached the end of its cables, falling a bare twenty feet short of completing its mission. It didn't stop spinning, but came winding back up the cable, at the same terrific speed with which it had left. * * * * * Bob sweated, having only fractions of seconds in which to maneuver for the "yo-yo" could strike a fatal blow at the hauler too. It was ticklish work completely to nullify the "yo-yo's" speed. Bob used exactly the same method of catching the "yo-yo" on the blunt nose of the ship as a baseball player uses to catch a hard-driven ball in his glove--namely, by matching the ball's speed and direction almost exactly at the moment of impact. And now Bob's hours of practice paid dividends, for the "yo-yo" came to rest snugly, ready to be released again.