The fliers shot downward, and as a boulder-camouflaged entrance yawned open in the mountain's side Worsel closed up and shot out a widely enveloping zone of thought-screen. The Overlords' control vanished. The Velantians, realizing instantaneously what had happened, flew madly back to their ship. They jammed through the air locks, flashed to their posts. The cavern's gates had closed by then, but the monsters had no screen fit to cope with the _Velan's_ tremendous batteries. Down they went. Barriers, bastions, and a considerable portion of the mountain's face flamed away in fiery vapor or flowed away in molten streams. Through reeking atmosphere, over red-hot debris, the armored Velantians flew to the attack. The Overlords had, however, learned. This cavern, as well as being hidden, was defended by physical, as well as mental, means. There were inner barriers of metal and of force, there were armed and armored defenders who, dominated completely by the monsters, fought with the callous fury of the robots which in effect they were. Nevertheless, against all opposition, the attackers bored relentlessly in. Heavy semiportables blazed, hand-to-hand combat raged in the narrow confines of that noisome tunnel. In the wavering, glaring light of the contending beams and screens, through the hot and rankly stinking steam billowing away from the reeking walls, the invaders fought their way. One by one and group by group the defenders died where they stood and the Velantians drove onward over their burned and dismembered bodies. Into the cavern at last. To the Overlords. Overlords! They, who for ages had preyed upon generation after generation of helpless Velantians, torturing their bodies to the point of death and then devouring ghoulishly the life-forces which their mangled bodies could no longer retain! Worsel and his crew threw away their DeLameters. Only when it is absolutely necessary does any Velantian use any artificial weapon against any Overlord of Delgon. He is too furious, too berserk, to do so. He is scared to the core of his being; the cold grue of a thousand fiendishly eaten ancestors has bred that fear into the innermost atoms of his chemistry. But against that fear, negating and surmounting it, is a hatred of such depth and violence as no human being has ever known; a starkly savage hatred which can be even partially assuaged only by the ultimate of violences--by rending his foe apart member by member; by actually feeling the Delgonian's life depart under gripping hands and tearing talons and constricting body and shearing tail.