"Well, it's happened," he said. "Instead of a stern chase, which would give us some chance of spotting them, they at once got off to the side and have all this time been flanking us. Now they're cutting in, straight behind, no doubt ready for business. All right. Ban, sound the alarm."

Like a gladiator about to step sword in hand into the arena, the Sandra, though a ship never designed for space duels, girded her loins and made herself ready for what at its best could only be an unequal struggle. She was outclassed in weapons, weight and speed—in all save pilots. She had Hawk Carse at her helm.

The harsh alarm bell at once rang through the ship, an emergency call to stations. Carse, at the controls, rapped out another order.

"Defensive web on, Ban, and build up power for the ray batteries."

As the echoes of the bell died, a piercing whine grew amidships, and shreds of blue light swiftly scattered by the Sandra's ports. They were quickly gone, but they left behind an almost invisible envelope of blue which enwrapped the ship completely. The defensive web against attacking rays was on.

Friday tumbled into the control cabin, and on his heels two of Leithgow's assistants, the third being on duty with the patients. Carse briefly explained what had happened. "Friday," he ordered, "you take the stern ray batteries. Ban—"

But Ban Wilson had returned to the electelscope, and it had given him more news. Interrupting, he cried out:

"They must be attacking! A light just flashed in the dome!"

With his words they all saw the light. The visi-screen, though it did not reveal the asteroid, showed the first weapon with which it struck—a lustrous ray of purple which in a blink had leaped out to the Sandra and enfolded her. A shower of sparks crackled out from the ship's defensive web, but the purple ray continued.

"I don't know that ray, Eliot." Carse said. "What's on our speed indicator?"