Behind the metal men, both Lucero and Verdugo maneuvered for position, their atomo-pistols blazing a path through scientific instruments and furnishings as they fired over and around the struggling robots. The awesome din of the gigantic battle was deafening, as the compartment was slowly converted into shambles. Once Alcoran managed to grip the leg of Lucero's robot and the latter went crashing against the vivisection table, instantly pulverizing it. But with a leap that carried it half across the vast alcove, the robot charged Alcoran like a battering-ram and driving him into the Tele-Magnum room with the impetus of his leap. The explosion of shattered tubes and crashing metal, the singing hum of ripped berlyloy and pulverized plastuco, was drowned by the clang and thud of the gigantic bodies as they strove to wrench each other apart. And now, only the litter-strewn floor was between Lucero and Verdugo, the latter oozing blood from a seared shoulder where an atomoblast had touched. Deliberately she aimed her atomo-pistol, even as the surgeon simultaneously raised his, but her blast only disintegrated a fulgurant on the ceiling, while Verdugo's fatal pencil of violet light speared an empty spot, for at that instant the hurtling form of Alcoran spewed from the alcove, barely grazing the girl, but such was the terrific force of his passage that it knocked her spinning against the wall where she collapsed. Behind Alcoran, hurtling like an avenging angel, Lucero's robot came charging with but one thought--destruction. "Alcoran!" It was Verdugo shouting hoarsely at his creation, now spread-eagled on the floor. "Run, follow me!" He dived for the passageway as Alcoran, damaged as he was, his brain shaken by the terrific concussion arose and sped after him. At the sight of the fallen girl, Lucero's robot checked his rush, hesitated and finally bent over her. He raised the still form as if it were a feather and stood for a moment as if trying to cerebrate. Finally it deposited her with infinite care on the couch where Verdugo had slept. Then it began to search what cabinets had not been destroyed, for a stimulant. It found the decanter of Thassalian, that miraculously had escaped destruction; gently opening the girl's mouth the robot poured a few drops down her throat. Just then Mark Lynn and Palanth burst into the room. Shamble was before their eyes. Mark went white with apprehension and leaped to Lucero's side, but the robot placed a formidable metal hand against the earthman's chest and growled: "Back, Terran! Come no nearer!" * * * * * Palanth slid toward them atomo-pistol in hand, just as Mark drew his. But at that moment Lucero opened her eyes and groaned softly. "Mark!" There was a universe of gladness in her cry. She waved a limp hand toward the robot. "This is Mark Lynn and the other's Palanth--your masters also, obey them."