Rick hesitated before he turned off the gun. When he finally did, a great feeling of relief came over him. Word-lessly, he began to walk to the plane. Soon, he and Joe were sitting inside it, watching the night sky through its crystal fuselage.
Joe broke the silence. 'Green is a man with connec-tions. Some are legitimate, most aren't. He gets his hooks into people, and then he uses them. He got me several years ago.' Joe sighed. 'It's a long, sad story. Anyway, he got connected with Sam somehow. That's what we called the guy with the time machine. I don't know his real name, probably something unpronounceable. He was an arrogant asshole and weird-looking, too—tall, baby-faced. Dressed like some guy from India. Wore an old-fashioned turban and had one of those dots on his forehead. He may have looked like a foreigner, but he spoke perfect English.
'Sam sought Green out, at least that's my impression. He had some scheme going, and he needed a native to carry it out. I never found out what the deal was about. Whatever it was, it was definitely illegal in the future. Sam was nervous as hell about getting caught in the twenty-first century. That's how I got involved. Sam wanted to do all the planning here.'
'Why?' asked Rick.
'Because it was safe.'
'Safe?'
'Manned time travel is banned in Sam's era, he wanted to go to someplace private.'
'Then why go somewhere built by people from the fu-ture?'
'I don't think he had a lot of choices. From the little I know about it, navigating through time is mind-bogglingly complicated. I suspect this was one of the few places.he knew how to reach.'
'I still don't understand why it would be safe.'
'Sam never told me why. I can only speculate. Maybe it's off-limits. Maybe it no longer exists in the future. That seems more likely.'
'Now you've really lost me.'
'Time travel becomes illegal when people figure out that traveling downwhen can alter their own present. Af-ter that discovery, time exploration is only done covertly by unmanned probes. Sam knew visiting our time would change history, and I suspect that was the point. It's likely he also altered events to erase knowledge of this place in the future.'
'If he did that,' said Rick, 'how could he know it still exists?'
'If Sam initiated the change, he'd be unaffected by it. What you do in the past only affects the future. He wouldn't be in the future when the change occurred.'
'That's what Green told Greighton,' said Rick. 'That they could change the future with impunity. If that's true, what did Sam have to worry about? He could wipe his pursuers out of existence.'
'I imagine a change of that magnitude would not be easy to pull off. Also, he'd have to worry about betraying his presence. Cause and effect gets very tricky in time travel. As soon as Sam appeared in our time, his presence made changes that could be detected in the future. All the clues of a person's whereabouts—hotel records, com- munications logs, all kinds of stuff—would instantly ap-pear upwhen.'
'It would be like looking for a specific grain of sand on a beach,' scoffed Rick.
'These people discovered time travel, Rick. Who knows what they're capable of? Sam did, and he was seriously worried about it. I imagine Greighton's unex-plained two-week absence will be a red flag to them.'
'Two-week absence!' said Rick. 'I was told this trip would take up only a few seconds in our own time.'
'It's easy to see why Green wanted you to believe that, but it's not true. Something Sam called 'temporal link-age' prevents that.'
'Temporal linkage? What's that?'
'It's really pretty simple,' said Joe. 'Imagine a target range inside a moving airplane where I've locked my gun on the bull's eye so I can hit it every time. I can do this because the gun and the target are moving together, linked by the aisle of the airplane. A temporal linkage works the same way, except the target and the gun are moving through time, not space. Sam set up the link to simplify navigating the time machine. Our own time and this time seem like fixed coordinates only because there's an inflexible connection between them. In practical terms, it means that if I spend three days in the past and want to return to my own time, I can only return to a time three days after I left. It works the same in reverse.'
'Crap! I'll miss two exams!'
