barrel retracting. It swung--

"Don't move!" Dorle cried. The barrel swung past them as they stood,
rigid and still. For one terrible moment it hesitated over their heads,
clicking and whirring, settling into position. Then the sounds died out
and the gun became silent.

Tance smiled foolishly inside his helmet. "I must have put my finger
over the lens. I'll be more careful." He made his way up onto the
circular slab, stepping gingerly behind the body of the gun. He
disappeared from view.

"Where did he go?" Nasha said irritably. "He'll get us all killed."

"Tance, come back!" Dorle shouted. "What's the matter with you?"

"In a minute." There was a long silence. At last the archeologist
appeared. "I think I've found something. Come up and I'll show you."

"What is it?"

"Dorle, you said the gun was here to keep the enemy off. I think I know
why they wanted to keep the enemy off."

They were puzzled.

"I think I've found what the gun is supposed to guard. Come and give me
a hand."

"All right," Dorle said abruptly. "Let's go." He seized Nasha's hand.
"Come on. Let's see what he's found. I thought something like this might
happen when I saw that the gun was--"

"Like what?" Nasha pulled her hand away. "What are you talking about?
You act as if you knew what he's found."

"I do." Dorle smiled down at her. "Do you remember the legend that all
races have, the myth of the buried treasure, and the dragon, the serpent
that watches it, guards it, keeping everyone away?"

She nodded. "Well?"

Dorle pointed up at the gun.

"That," he said, "is the dragon. Come on."

* * * * *

Between the three of them they managed to pull up the steel cover and
lay it to one side. Dorle was wet with perspiration when they finished.

"It isn't worth it," he grunted. He stared into the dark yawning hole.
"Or is it?"

Nasha clicked on her hand lamp, shining the beam down the stairs. The
steps were thick with dust and rubble. At the bottom was a steel door.

"Come on," Tance said excitedly. He started down the stairs. They
watched him reach the door and pull hopefully on it without success.
"Give a hand!"

"All right." They came gingerly after him. Dorle examined the door. It
was bolted shut, locked. There was an inscription on the door but he
could not read it.

"Now what?" Nasha said.

Dorle took out his hand weapon. "Stand back. I can't think of any other
way." He pressed the switch. Th