I heard the woman screama thin, racking shriek. The brue slithered eagerly forward. The woman tried to cast the child off the platform into the water. The insect caught it.

I looked away. Tama and Rowena were shrinking, trembling against me. Roc and Jimmy were staring transfixed. "Mercifully, the ball turned on its axis. The window showed only a section of the city where all the houses were leveled and the blackened bodies were lying inert. I saw other brues: swimmingstopping to seize upon somethingeatingcasting it away.

Then from the distant terraces, where the invaders now were withdrawing, a shrill, mechanical whine sounded. A siren call; it sang over the valley and echoed back from the cliff walls. The call for the brues. We could see a hundred or more of them appearing in the wreckage. Swimming in the demolished streets, slithering over the marsh shores, and up the terraces to join their masters.

Our vehicle had been seen and recognized. Groups of men stood gazing up at us. A flare rose vertically up from them, as a signal.

The ball had turned toward the center of the city. We had risen againan altitude of about a thousand feet over the water. Dorrek and Muta still stood at their window, engrossed in their thoughts.

I whispered to Roc, "Now is our time! Order us back behind the hills, the way we came. Tell Dorrek to land us there." Roc nodded agreement. He advanced across the room toward Dorrek. Jimmy and I stood tense where we were. I whispered, "Watch them, Jimmy! Your flash ready? If Dorrek rebels, we can kill him from here and hold this room against the others." If only we had done that! And yet, Dorrek's men in the other room had control of the vehicle. The door was open beside us, but we were still a thousand feet in the air.

Roc, cylinder in hand, reached the center of the room.

Dorrek turned to face him. Tama and Rowena had moved aside, closer to the open doorway. But closer, also, to Dorrek.

Roc gave his command. Dorrek stared. Again there was that instant of electrical tenseness. Would the giant obey? He stared at Roc impassively for an instantand then he leaped. My beat-cylinder was out but I could not use ltl I held my impulsive finger from the trigger. With my left hand I struck at Jimmy's rising weapon, and shouted in horror to Roc.

For Dorrek had leaped, not at usbut upon Rowena I She had passed within a few feet of him. Like a huge leopard, without warning he whirled and pounced upon her and seized her. There was an instant when he was struggling with her, and with Tama. Rowena was taken too much by surprise to get her knife from the dressing gown pocket.

Dorrek's arms went around her from behind. As she struggled with him, twisting, clutching backward over her shoulder at his face, Tama came at them. Her knife went into Dorrek's arm. He shouted with an infuriated roar of pain. Muta dashed heavily forward. A sweep of Tama's wing knocked the woman back. Dorrek, holding the struggling Rowena before him as a shield, retreated against the wall. Again, like a wrathful, desperate bird, Tama with spreading wings buried herself at them.

Within an instant the little room was a chaos of strife.

Whatever plans we had were discarded now. No time to think, even to realize what we were doing. Against the open door, the giant Dorrek fought with the two girls. Muta had turned aside, crouching, watching. I saw her stoop for Tama's fallen knife.

Jimmy and I were rushing forward. Roc made a leapthen fell. Dorrek's weapon spat a blue bolt. It hissed overhead, struck the metal ceiling with a rain of falling sparks, crackled into the metal and was absorbed. I felt the heat of it; I thought Roc had been hit, but in a moment I saw him up again.

Jimmy and I did not dare fire. As we plunged those few steps forward toward Dorrek, Jimmy screamed a warning, "Jackbehind you!" Half turning, I saw three of Dorrek's men crowding through the doorway. One flung a knife. I turned in time to see it coming; the heavy handle of it struck me in the forehead.

There was a moment of blackness. But at once my senses came back. I was on the floor, with two of the Mercurians upon me. I found myself stfll clutching the ray gun. My revolver had fallen from my bootwas gone. Hands were plucking at me. A heavy shoulder pinning me, another body on my legs.

I lunged, twisted with returning strength. Above me I heard Jimmy's shouts, then Roc's. A turmoil of staggering footsteps; the thud of blows; the beat of Tama's wings; a scream. A man's scream of agony. The thick body of a Mercurian man fell on me and my antagonists as we struggled.

Then another hiss over me; Roc's weapon, I thought. I saw a gray figure lunge past me, meet the heat bolt and fall.

A hand and knife came down with a stabbing blow. I jerked away from it, fired my cylinder into a flat gray face bending down at me. The face went black, sank backward. The stench of burned flesh was around me as I heaved off restraining arms and staggered to my feet.

The room was crowded with struggling forms and clouded with vapors: the acrid gas of the bolts, the smell of charred flesh. The lights were out; the place was dim with the outside daylight. I stumbled over a body on the floor as I took a step. I saw the outlined window ovals, and the rectangle of open doorway. Tama was there, in the grip of a Mercurian. Roc and Jimmy were rushing at them. I found myself reeling against Dorrek, who still held Rowena. We were in the center of the room. I leaped upon them, struck at the giant's face, and felt another antagonist thud against me from behind. Then a stab of pain as a knife blade went into the flesh of my shoulder.

At the doorway, silhouetted against the outside light, four figures were entangled in a struggling mass: a Mercurian maii, Tama, Jimmy and Roc. They toppled at the threshold the brink of a void with a thousand-foot drop to the Water City beneath us. I saw Tama and Roc go over the brink, and Jimmy with them! The Mercurian swayed, fought for his balance. Jimmy's disappearing hand made a last clutchcaught the Mercurian's leg, and pulled him oVer.

The rectangle of doorway was empty. I struck again at Dorrek, trying to pull Rowena from him. The man behind me pounded at my head with a ray-cylinder. I crumpled to the floor as I felt my senses going.

IX SUSPENSE GUY AND TOH waited impatiently in a room of Guy's apartment in the palace at Hill City. Some twelve hours earlier, Dr. Grenfell had brought the Flying Cube to a safe landing.

But they had lost sight of the Mercurian sphere in clouds of smoke and fog, and with it their hopes of finding Tama and Rowena, Jimmy and me.

"But, Guy, what are we to do?" demanded Toh. "What does Dr. Grenfell say?"

"What can he say? We have no idea where the ball landed. Girls have been flying here to the Hill City from everywhere. You must talk to them, Toh."

"I havel Alwaysnone have seen it." Guy seized the little Mercurian youth. "Toh, I'm as eager as you-desperate. Tama, off there somewhere" He choked on his words.

They had reached the Hill City only to find chaos. News of the unexpected invasion from the Cold Country had just come, brought by girls flying from the outlying districts. The twelve hours that followed were a blurred turmoil to Guy.

The shocked, frightened government of the Light Country received Guywhom they knew welland bis friendly companions from Earth with pleasure at having them as allies. The Flying Cube, with its Earth weapons and its crew of five men in addition to Grenfell was an asset in the war.

Grenfell, as he afterward told me, was startled by this sudden crisis into declaring his Earth party as active allies and participants. His first instinct was reluctance. With scientific foresight he appreciated the new era of interplanetary relations, at the threshhold of which he now stood as a pioneer. He was upon Mercury, meeting the inhabitants of this other world as a representative of the Earth. He had planned coming merely as a friendly visitor; but it was imavoidable that he should not be in pursuit of Mercurian outlaws who had abducted an Earth girl.