Again that circular thinking. It increased the pain in her head when she thought like that. She pushed those thoughts from her mind and slipped her vanished duplicate's pendant into a pouch at her waist. Then she put her arms up in front of her face to protect her eyes from the flames, and took a step toward her past self.

The heat was so intense it burned the sleeves of her uniform. She stepped back and looked down at her prosthetic arms. The specially formulated plastic had melted away, exposing their metal skeleton and electronics.

Again she looked at the wall of fire. The heat was too intense. Her prosthetic arms would not survive if she stepped through those flames.

As she watched, her past self moved. Still without life in her expression, that other brought her arms up before her own eyes, then stepped toward Susan, through the wall of flame.

This jump was the worst she had yet experienced. She made half a dozen attempts before she finally left Defiant, and arrived back in her proper time. The resulting physical effects were nearly dehabilatating.

She stood trembling in the corridor outside Hyatt's office, the headache pulsing behind her eyes. Her uniform was soiled, stained, torn, and burned, and her hair and eyebrows were singed. Beneath dirty rag bandages, the plastic covering her prosthetic arms and hands was melted away, exposing their complicated electronics and mechanics. The first thing she had done, after bringing her past self somewhat out of shock, was to bandage them, so neither her past self nor Defiant's crew would see them. She didn't want that crew any more panicked than it already was.

The previous forty-eight hours had been horrible. For two straight days she had helped her past self battle fires, dress wounds, and comfort the dying. She was exhausted-both physically and mentally.

Somewhere in all that, someone had bandaged her head, although she could remember neither who nor when. But the pain in her head did not come from the crack her future self had given her with the blaster butt. This headache had been caused by a multitude of jumps through time.

Then the snowflake pattern appeared in her mind, and she began mouthing the mantra. It did still less good this time than it had the times before-more of the headache remained when she was finished reciting the chant than had the last time.

Susan stepped to the door and it irised open. The outer office was empty. She went through to the door to the inner office, and it opened as she approached. Within, the future Hyatt sat behind the desk, going through a stack of computer printouts. The blaster pistol rested on the desk within quick reach.

"So, you are back," he said, looking up from the stack of papers. His hand went to the pistol, rested on it, but he did not pick it up.

Susan took what she hoped was a casual step toward the desk and nodded. If she could bluff him into thinking she was the other Susan, her future self…

Hyatt picked up the pistol and pointed it at her. "It won't work," he said. "Step back." He waved the pistol in her direction.

"How did you know?" she asked as she stepped away from the desk. "How could you tell?"

He smiled. "I wasn't really expecting the other Susan back. That's the way it had to be."

"Had to be? You mean, my duplicate actually knew she wouldn't succeed?"

Hyatt nodded. "Of course she knew."

"Then why even try?"

"Because she had to, because she had watched herself try five years ago, in your place. Remember, she already experienced everything you just went through." Again, that circular thinking.

"But if she had succeeded-if she had killed our past self-she would have died, too."

"Not necessarily. Only if she had lost her pendant after she'd killed that past self. And she would have taken your pendant as soon as she'd killed that other. At that point, you would have ceased to exist."

"That's what I mean," Susan said. "She was taking the same chance. She was putting herself in jeopardy, as well."

Hyatt nodded. "But it had to be done. First, because it was done. And it was worth any risk to stop you."

"And so I killed her…"

"You killed her?"

Susan nodded. "I snatched the pendant from around her neck, and she vanished."

Hyatt laughed. "Then she isn't dead."

"What?"

"It's like cutting a stretched rubber band," he said, motioning Susan to the chair before the desk. She sat, and he kept his hand on the blaster. "She was snapped back to our time, five years into the future. Had she succeeded in killing your past self, then had you taken her pendant, she would be dead. But your mutual past self lives." He shook his head.

Susan still couldn't believe what she was hearing. It all seemed so horribly strange.

After a few seconds, she said, "There are only four of you in on this, then." More a statement of fact than a question.

"No, there are only two from your future-myself and your double. Krueger, of course, was hired here, in this time."

"But what about the short belter, and the tall man outside the curio shop on Fleet Base?"

"I'm afraid they aren't with us."

"Then who are they with? They both wore pendants."

"That is interesting. But I assure you, I do not know. Originally, there were only two pendants."

Susan reached into her breast pocket and pulled out the pendant she had ripped from around her future self's neck. The old man's gaze went from that pendant to the one she wore around her neck, while his hand strayed to his own.

"I assure you," he said, "originally, there were only two pendants. Everything has become so mucked up-probably because of your indiscriminate jumps, as well as our own jumps while attempting to stop you."

Again Susan thought of the belter, and the tall man in the corridor outside the curio shop. Both had worn a pendant. And the old man in the shop had said the man who had sold him the pendant she now wore had possessed another those many years ago.

As if he could read her mind, Hyatt asked, "Where did you get the one you have been using?"

"That isn't important," she said.

"It might be extremely important. Don't you see that?"

He was right, of course. But Susan knew she couldn't tell him. Such knowledge might be just what he needed to use against her.

"Where did you get your pendants?" she asked.

"They were found on a cinder of a planet circling the Crab Nebula's star of origin," he answered.

"And there were only the two of them?"

He nodded.

"What are they?"

Hyatt shrugged. "Artifacts from some ancient civilization, I imagine. What use their creators put them to, we have no idea."

They were both silent for several seconds. Finally, Hyatt lifted the blaster pistol from the desk, then held his other hand out to Susan, palm up. "Let's have them, Captain," he said.

Susan got to her feet. "No," she said, defiantly. "If you want them, you will have to kill me." She took a deep breath, then took a step toward him.

And he silently disappeared.

The pounding behind her eyes increased, and the snowflake pattern formed in her mind. The mantra came to her lips.

But that couldn't be. It shouldn't be happening. She had jumped-not he.

Yet she hadn't, and he had!

And there was something more, something she could never have expected. Somehow, she could sense the old man's track. She could actually feel the thread of his existence, observing him as he made a jump through time and space. He came to rest in an empty conference room elsewhere in the Survey Service compound, two weeks in the future.

With an effort, she brought the picture of the conference room resting in her mind into sharp focus. She concentrated on every small detail-bare walls, gray metal table, utilitarian straight-backed chairs. Even the sign on the wall denoting the after-hours use of the room as a holo-vid viewing area.