The decision was made for them by the rhinosaur. The great scaled beast began to turn around, crashing down brush as he moved. In a few seconds he would be facing directly toward them.

"Tree," Baba clicked very softly. Johnny nodded. The two slinked like hunting cats toward the tree. They didn't dare look back.

"I think the guard saw us," Baba clicked. "He was waving his arms." The jewel bear had already climbed part way up the trunk. He motioned for Johnny to grab the harness.

Not making a sound Johnny took hold of the harness, and the two of them started up the tree. When they reached the first branch, Johnny let go the harness and clambered up as quickly and quietly as he could. Only when they were screened from view by the fleshy leaves of the meat tree did he dare to look down.

Through little openings between the leaves he could see the rhinosaur. It was shaking its ugly horned head. Its little black-blue eyes peered about under blue scaled eyelids. It trumpeted. The deep blasting sound echoed against the settlement walls. For some minutes it moved around in the brush, snorting. It paused, snuffing in air in great gulps. Then it headed straight for the tree and began to trot back and forth under it.

It had smelled Johnny!

Its hoofbeats on the ground made the limb Johnny sat on tremble. If the rhinosaur sensed that Johnny was in the tree it was the end. The tree was easily four feet thick at the base, but a rhinosaur could knock it down with one rush. Johnny and Baba were on the highest and smallest branch, but they were barely twenty feet above its head.

The rhinosaur's shoulder brushed against the lowest branch and the whole tree swayed back and forth as if hit by a hurricane.

Johnny was struck by an idea. "Baba," he whispered, "do you think it might obey you—just like the arrow-birds?"

"I don't know, Johnny," Baba clicked softly. "I'll try."

Baba started to climb down. By the slow careful way Baba moved, Johnny knew the little bear was afraid, too. It was an awful chance to take. Johnny was about to call him back, but as he opened his lips, the little bear looked up and grinned.

Down Baba went. He was now halfway down the tree, thirty feet from the ground and level with the eyes of the rhinosaur. It caught sight of him, snorted, and pawed the ground, digging up shovelfuls of dirt with each movement.

"Friend-pet! Friend-pet!" Baba clicked and Johnny suddenly wanted to giggle. Imagine having something that size for a pet!

"Friend-pet!" Baba clicked again, "Go away! Go away! Bother us not!"

The big creature stopped still. Muscles rolled and bunched under the heavy blue-grey scales. Was he going to charge or leave?

They never found out.

There was a roar of motors behind the beast, the clank of metal, the deafening blast of an ato-tube gun. The ground shook; leaves showered down on Johnny.

The guards had sent a tank to rescue them!

Things began to happen too fast for Johnny to keep track. The rhinosaur roared with pain and wheeled. It had been hit! It charged toward the oncoming tank—one of the colony's light duty tanks, built for speed and quick turns. The driver jockied for position. The tank shot down the clearing, turned and stopped. Its guns were too light to kill the huge beast, so the gunner did not bother to fire again. They were trying to draw the rhinosaur away from the tree.

The rhinosaur's hooves thundered, echoing against the walls and the rocks as it gathered speed. It was almost on top of the tank. With a roar of the motors the tank shot forward. The rhinosaur was going too fast to stop or turn. It plunged on past the tank, bellowing its rage.

Almost immediately the tank screeched to a stop beneath the tree. Its manhole swung open. Rick Saunders' red head emerged.

"Get in here! Quick!" he shouted over the noise of the motor.

Johnny needed no invitation. He was already halfway down the trunk of the tree. Baba jumped from his perch into the open manhole. As soon as Johnny was low enough, he grasped a branch, swung on to the top of the tank, and started down the steel ladder. The tank jumped forward with a lurch.

The rhinosaur was bearing down on them. Their guns roared, but the rhinosaur did not stop. As a hand grabbed him, pulling him inside, Johnny saw the tree topple over as the rhinosaur crashed into it.

"Fire the gate rocket!" someone's shout echoed in the tank. Johnny recognized Captain Thompson's deep voice.

"Check!" Johnny heard Rick answer. Rick was up in the gun turret.

After the outside light, it seemed very dark in the tank. It smelled of grease and the burnt air of cannon fire. There was the swish of a rocket. Johnny knew this rocket was a signal for the guard on duty at the steel gateways to be ready to open up.

The motors were roaring with a high whining sound which meant they were going at full speed. The tank bounced and jolted, shaking Johnny from side to side.

"Get ready for the gate!" warned Captain Thompson from the driver's seat. The tank seemed to be almost flying now. Johnny set himself for a violent turn. Like the doors of the houses, the wall gates were double. Each was a heavy steel portcullis, a great sliding door that could be raised and lowered. When a tank came in the outer gate its weight tripped a switch. That switched turned on motors that made the first gate fall and the second rise. Otherwise fast moving tanks would have smashed into the second gate.

Johnny slid over to an observation slit. To his left he could see that the heavy steel gate was rising. His heart raced. When being chased by rhinosaurs a driver sped straight along the wall and then turned sharply through the open gate. If he timed it right the rhinosaurs plunged on and the tank was safe. It took split second timing.

They were right by the gate. Johnny grabbed a brace. With a scream of the treads, the tank started into a turn.

"Rhinos on the side!" shouted Rick. His guns blasted.

Captain Thompson fought to straighten the tank out of the turn. Baba was sitting with his paws over his ears, his claws glowing.

There was a bone-shattering crash.

Then Johnny felt himself flying through the air. Everything went topsy-turvy. He banged his shoulder against the side of the tank. Then he felt Baba's furry body against his. Rick's feet seemed to come from nowhere and dig into his back. Johnny grabbed on to something solid and wedged himself in tight.

The tank was rolling over and over. Something crashed against it again and again. There was a heavy thud and the sound of breaking metal. Then everything was still. The motors had stopped. From outside came the roar of guns and the bellowing of rhinosaurs.

Johnny found himself sprawled on top of Rick Saunders. He was terribly shaken. Baba was hanging onto one of the rungs of the steel ladder. It was almost pitch dark. Rick struggled to his feet as Johnny scrambled from on top of him.

"We're upside down," Baba clicked softly to Johnny.

"What happened, Saunders?" Captain Thompson's heavy voice demanded from the driver's compartment. "Didn't Harkness teach you to shoot?"

"Four of them rushed us right at the gate," Rick answered. "Did we make it inside?"

"Think so. Anybody hurt?" Thompson asked.

"Just scratched a little," Johnny answered.

"Good," Captain Thompson grunted. "Is the righting jack O.K.?"

Rick tested a lever.

"O.K."

"Let her rip!"

"Hang on, Johnny," Rick said. "We're going to right her."

Johnny knew just what was going to happen. A tank turned turtle had meant a dead crew until the righting jack had been attached to each of the tanks. Compressed air pushed out two rods fore and aft and flipped the tank right side up.

Johnny braced himself. There was a rush of air. Johnny felt the tank tip slowly under him. Then it went over with a crash. The tank was right side up.

"The gate!" Rick exclaimed.

Just above his head Johnny saw light from the observation slit. He looked out. Then he knew what Rick meant. They and the four rhinosaurs had reached the gate at the same time. The rhinosaurs were inside. They had knocked the tank through the outer gateway and had smashed into the steel door before it was halfway down.

The inner door must have met the same fate for Johnny could see that the sliding steel plates were bent and jammed open. The rhinosaurs had kept after the tank until now it lay fifty yards inside the settlement. Even as Johnny watched, another rhinosaur charged through the opening and headed into the settlement.

Captain Thompson was grinding on the starter and Rick was working up in the gun turret.

"The rhinosaurs got through," Johnny clicked to Baba.

"And the tank is broken?" Baba clicked back.

"Yes."

"I have to get out," Baba said. "Maybe I can get the rhinosaurs to...."

"No, Baba," Johnny said. "They're just plain crazy now."

Captain Thompson climbed down out of the driver's compartment.

"The motor's gone. How are the guns?"

"Out of action," Rick answered. "Must be filled with dirt. We can't do any good here."