The green man nodded. "Yes, though I still think such a thing's impossible."

"Probably is," Norman admitted. "But it's the one chance we've got, the immensely greater strength of our Earth-muscle that the frog-men must have forgotten when they put us in here."

They moved silently to the room's great barred door, outside which a frog-guard paced. They waited until he had pa.s.sed the door and on down the hall, then Norman and Hackett and Sarja grasped together one of the door's vertical bars. It was an inch and a half in thickness, of solid metal, and it seemed ridiculous that any men could bend it by the sheer strength of their muscles.

Norman, though, was relying on the fact that on the second satellite, with its far lesser gravitational influence, their Earth-muscles gave them enormous strength. He grasped the bar, Hackett and Sarja gripping it below him, and then at a whispered word they pulled with all their force. The bar resisted and again, with sweat starting on their foreheads, they pulled. It gave a little.

They shrank back from it as the guard returned, moving past. Then grasping the bar again they bent all their force once more upon it.

Each effort saw it bending more, the opening in the door's bars widening. They gave a final great wrench and the bent bar squealed a little. They shrank back, appalled, but the guard had not heard or noticed. He moved past it on his return along the hall, and no sooner was past it than Norman squeezed through the opening and leaped silently for the great frog-man's back.

It went down with a wild flurry of waving webbed paws and croaking cries, stilled almost instantly by Norman's terrific blows. There was silence then as Hackett and Sarja squeezed out after him, the momentary clamor of the battle having aroused no one.

The three leaped together toward the stairs. In two great floating leaps they were on the floor above, Hackett and Norman dragging Sarja between them. They were not seen, were sailing in giant steps up another stair, hopes rising high. The last stair--the roof-opening above; and then from beneath a great croaking cry swelled instantly into chorus of a alarmed shouts.

"They've found the door--the guard!" panted Hackett.

They were bursting out onto the roof. Frog-guards were on it who came in a hopping rush toward them, force-pistols raised. But a giant leap took Hackett among them, to amaze them for a moment with great flailing blows. Sarja had leaped for the nearest flying-boat resting on the roof, and was calling in a frantic voice to Norman and Hackett.

Norman was turning toward Hackett, the center of a wild combat, but the latter emerged from it for a brief second to motion him frantically back.

"No use, Norman--get away--get away!" he cried hoa.r.s.ely, frenziedly.

"Hackett--for G.o.d's sake--!" Norman half-leaped to the other, but an arm caught him, pulled him desperately onto the boat's surface. It was Sarja, the long craft flying over the roof beneath his control.

"They come!" he panted. "Too late now--" Frog-men were pouring up onto the roof from below. Sarja sent the craft rocketing upward, as Hackett gestured them away for a last frantic time before going down beneath the frog-men's onslaught.

The roof and the combat on it dropped back and beneath them like a stone as their craft ripped across the silvery dusk over the mighty frog-city. They were shooting toward the city's center, toward the green pool that was the entrance to the water-tunnel, while behind and beneath an increasing clamor of alarm spread swiftly. Norman raged futilely.

"Hackett--Hackett! We can't leave him--"

"Too late!" Sarja cried. "We cannot help him but only be captured again. We escape now and come back--come back--"

The truth of it pierced Norman's brain even in the wild moment.

Hackett had fought and held back the frog-guards only that they might escape. He shouted suddenly.

"Sarja--the water-tunnel!" A half-dozen boats with frog-guards on them were rising round it in answer to the alarm!

"The force-gun!" cried the green man. "Beside you--!"

Norman whirled, glimpsed the long tube on its swivel beside him, trained it on the boats rising ahead as they rocketed nearer. He fumbled frantically at a catch at the gun's rear, then felt a stream of sh.e.l.ls flicking out of it. Two of the boats ahead vanished as the sh.e.l.ls released their annihilating force, another sagged and fell.

From the remaining three invisible force-sh.e.l.ls flicked around them, but in an instant Sarja had whirled the boat through them and down into the water-tunnel!

Norman clung desperately to his seat as the boat flashed down through the waters, and then, as Sarja sent it flying out through the great tunnel's waters, glimpsed, close behind, the beams of the three Rala boats as they pursued them through the tunnel, overtaking them. Could the force-sh.e.l.ls be fired under water? Norman did not know, but desperately he swung the force-gun back as they rushed through the waters, and pressed the catch. An instant later beams and boats behind them in the tunnel vanished.

His lungs were afire; it seemed that he must open them to the strangling water. The boat was ripping the waters at such tremendous speed that he felt himself being torn from his hold on it. Pain seemed poured like molten metal through his chest--he could hold out no longer; and then the boat stabbed up from the waters into clear air!

Norman panted, sobbed. Behind them rose the colossal metal dome of the frog-city, gleaming dully in the silvery light that flooded the far-stretching seas. That light poured down from a stupendous silver crescent in the night skies. Norman saw dully the dark outlines on it before he remembered. Earth! He laughed a little hysterically. Sarja was driving the flying-boat out over the sea and away from the frog-city at enormous speed. At last he glanced back. Far behind them lay the great dome and up around it gleaming lights were pouring, lights of pursuing Rala boats.

"We escape," Sarja cried, "the city of the Ralas, from which none ever before escaped!"

Remembrance smote Norman. "Hackett! Held off those frog-men so we could get away--we'll come back for him, by G.o.d!"

"We come back!" said Sarja. "We come back with all the green men of this world to the Ralas' city, yes! I know what Fallas has planned."

"Can you find your way to him--to your city?" Norman asked.

Sarja nodded, looking upward. "Before the next sun has come and gone we can reach it."

The boat flew onward, and the great dome and the searching lights around it dropped beneath the horizon. Norman felt the warm wind drying his drenched garments as they rushed onward. Crouched on the boat he gazed up toward the silver crescent of Earth sinking toward the horizon ahead. That meant, he told himself, that the satellite turned slowly on its axis as it whirled around Earth. It came to him that its night and day periods must be highly irregular.

When the sun climbed from the waters behind them they were flying still over a boundless waste of waters, but soon they sighted on the horizon ahead the thin green line of land. Sarja slowed as they reached it, took his bearings, and sent the craft flying onward.

They pa.s.sed over a green coastal plain and then over low hills joined in long chains and mantled by dense and mighty jungles, towering green growths of unfamiliar appearance to Norman. He thought he glimpsed, more than once, huge beastlike forms moving in them. He did see twice in the jungles great clearings where were fair-sized cities of bright-green buildings, a metal tower rising from each. But when he pointed to them Sarja shook his head.

At last, as they pa.s.sed over another range of hills and came into sight of a third green city with its looming tower, the other pointed, his face alight.

"My city," he said. "Fallas there."

Fellows! Norman's heart beat faster.

They shot closer and lower and he saw that the buildings were obviously green to lend them a certain protective coloration similar to that of the green jungles around them. The tower with its surmounting cage puzzled him though, but before he could ask Sarja concerning it his answer came in a different way. A long metal tube poked slowly out of the cage on the tower's top and sent a hail of force-sh.e.l.ls flicking around them.

"They're firing on us!" Norman cried. "This can't be your city!"

"They see our black boat!" Sarja exclaimed. "They think we're Rala raiders and unless we let them know they'll shoot us out of the air!

Stand up--wave to them--!"

Both Norman and Sarja sprang to their feet and waved wildly to those in the tower-cage, their flying-boat drifting slowly forward.

Instantly the force-sh.e.l.ls ceased to hail toward them, and as they moved nearer a sirenlike signal broke from the cage. At once scores of flying-boats like their own, but glittering metal instead of black, shot up from the city where they had lain until now, and surrounded them.

As Sarja called in his own tongue to them the green men on the surrounding boats broke into resounding cries. They shot down toward the city, Norman gazing tensely. Great crowds of green men in their dark tunics had swarmed out into its streets with the pa.s.sing of the alarm, and their craft and the others came to rest in an open square that was the juncture of several streets.

The green men that crowded excitedly about Norman and Sarja gave way to a half-dozen hurrying into the square from the greatest of the buildings facing on it. All but one were green men like the others.

But that one--the laughing-eyed tanned face--the worn brown clothing, the curious huge steps with which he came--Norman's heart leapt.

"Fellows!"

"Great G.o.d--Norman!" The other's face was thunderstruck. "Norman--how by all that's holy did you get here?"

Norman, mind and body strained to the breaking point, was incoherent.