"You're right," she said, and turned away. "Sherman, if he tries anything funny, shoot to disable."

"Right."

So much for undying love. And I was no fool; I put the stunner on the remains of Mayer's desk and went back toward my chair. Louise was already sitting, but I was too agitated to do anything but stand.

Louise had her elbows on the chair arms, and was massaging her forehead with the tips of her fingers. She looked very tired. She spoke without looking up.

"Sherman, there's something wrong with that stunner. Will you take a look?"

The robot picked it up, turned it over in his hands, then did something that made it split into two halves. There wasn't anything inside. It was just a plastic shell.

"I thought it felt light," she said, when he showed it to her. She looked at Mayer. "Doctor Mayer, I want to know -- "

"I prefer not to be called Doctor," Mayer said.

"Doctor Mayer," Louise said, pointedly, "this stunner belongs to me. One of my people lost it. I'd like to know where you got it: "Where did you lose it?"

"I'm asking the questions here."

"And maybe I'm not answering them."

Louise sighed. "Why don't we dispense with the melodramatic talk, Doctor?"

"That cuts both ways," Mayer said. I looked at him again. He was calm on the outside, but now I saw he was smouldering underneath. I guess I would have been, too, if somebody'd just ripped my desk apart. On the other hand, there was Sherman, and I thought Mayer was making a very dangerous stand "I lost the stunner about a week ago," Louise said. "In 1955."

"And I found it thirty years ago. Also in 1955."

Louise glanced at Sherman.

"I think he's lying," the robot said. Louise nodded, and gestured for Sherman to go to Mayer. As the robot did so, Mayer lost a little of his composure.

"Are you going to torture me?" he asked.

"Depends on how melodramatic you want to get." Mayer made an involuntary move away as Sherman took him by the arm The robot encircled Mayer's wrist with his huge metal hand, and waited, just holding it there.

"Did you find it youself?" Louise asked.

"Yes," Mayer said. Sherman shook his head.

"Who did find it?"

Mayer looked down at Sherman's hand, and then I did too, and I'll bet we both had the same thought at the same time: polygraph. Or the far-future equivalent, which I was willing to bet was better than the one used on me earlier that same day.

"That's right," Louise said, making me wonder if mind-reading was one of her many talents. "Now, we can play twenty questions and a lie will tell me as much as the truth, but it takes a while to zero in on it that way. We don't have a lot of time, but we do have some drugs that will make you tell all in about ten seconds though they tend to use up brain cells-

and we do have a heartless machine who can cause you a lot of pain if I give him the order."

I don't know if Mayer caught it, but Sherman gave Louise a quick glance. I couldn't swear to it -- I didn't know much about reading a robot's expressions -- but I thought he looked hurt.

Heartless, indeed. Sherman tank, my ass. A robot who had apologized to a computer terminal, presumably on the principle that it might be a distant ancestor? So I decided Louise was pulling some sort of bluff. I guess I should have told Mayer about it. I didn't, f wanted to hear his story at least as badly as Louise did. Maybe more.

I'd figured out why he hadn't told me about the stunner in his desk. L think he would have shown it to me if Louise hadn't interrupted us. He was simply doing what any good scientist would do, attacking my story, getting me to draw what I'd said I'd seen with no prompting from him.

Still, I was pissed off. I sat back and waited to see what he'd do.

"I thought you had all the time in the world," Mayer said.

"We did, once. Now we've only got a little, and you're using it up at a faster rate than you can imagine."

"Can't you tell me anything about-"

"Not yet. Maybe later. I make you no promises; it's still possible we can salvage this fiasco with minimal damage. It's no longer possible to save the whole world, but I hope to preserve a piece of it." She shrugged. "It's what I've done all my life, fighting a delaying action. Now, you will talk."

And Mayer did.

"There was a plane crash in Arizona in 1955," he began.

"I know. I was on the plane."

That stopped Mayer for a moment.

"Then you admit it?"

"Admit what? Oh, you think I made the plane crash. No, Doctor, it was nothing as simple or straightforward as that. We were saving the lives of everyone aboard that plane."

Mayer looked stunned. I probably did, too. I was about to say something, but Louise went on.

"Yes, Doctor Mayer. Your daughter is alive and well."

I couldn't begin to report what was said in the next half hour. Much of it was shouted, in an atmosphere of disbelief and anger. I won't even pretend that I understood much of it. I'm far from sure I understand most of it even now. Time travel, paradoxes, the end of the universe ... it was a lot to digest in one lump.

But she said she had been saving people's lives. The mechanism she described for doing it was so complicated and bizarre that the only way I had of believing any of it was a kind of reverse logic: if she was going to lie, why tell such an improbable lie? But if she was telling the truth ... it meant the blood and gore and suffering that had come to dominate my entire life was no more real than a corpse in a Hollywood mad-dasher movie. It meant all those people were alive somewhere, in an incomprehensible future.

"No, not all of them, Bill," Louise had said gently, at one point. "Only the crashes in which there were no survivors. Any witnesses to what we were doing would have caused a paradox"

It seemed a quibble to me. I felt such a load lifting from my shoulders ...

"We didn't catch it for a long time," Louise told Mayer. The fact that your daughter was aboard the plane."

"She was only twenty-two," Mayer said. He was weeping. "She had just been married.

She was on her way to California, to Livermore, to introduce her new husband to me and ... and Naomi. I think it killed Naomi, too, indirectly. She was my wife, and she "

Yes, we know," Louise said, gently.

"You know everything, don't you?"

"If I did, I wouldn't be back here questioning you. We didn't know your daughter was on that Constellation because she was traveling under her new last name. We saw you at the crash site, but couldn't find out why you were there. We finally pieced it together, with a lot of time-tank observation. We had to look at indirect things. We were up against a lot of temporal censorship." She glanced at Sherman. "And it wasn't until a short time ago we knew you had come into possession of the other lost stunner."

Mayer had purchased the thing from an Indian, who said he had found it a long ways from the main impact site. The Indian had told him the stunner would produce a not-

unpleasant tingling sensation when the trigger was depressed. Sherman and Louise looked at each other when Mayer said that. I don't know; maybe the battery was failing. The one I found sure as hell kicked harder than that.

"What I must know," Louise finally said, "is what happened to the insides of the stunner? Do you know?"

Mayer was silent. I was surprised. I didn't know what he might have to gain by continuing to hold out. I should have known, but by then I was reeling from too much information, too fast.

"He knows," Sherman said. The robot was no longer holding Mayer's hand; I guess he didn't need to anymore, or maybe it had never been necessary. Maybe it was just a show to impress the savages.