It was the Model T of time machines.
In the 25th century, the Dextron 4000 was the first time machine that any moderately rich person could afford. It was a sphere the size of a car, with a dashboard containing controls that allowed you to transport yourself backward to any time in the past 200 million years. Before any buyer was allowed to use the machine, he or she had to sign a contract promising never to go back in time and make any substantial alteration that might alter the trajectory of the past, causing the present to be changed. That type of modification was called altering a time-line, and it was the ultimate sin of time travel.
Each buyer of the Dextron 4000 also had to attend a training course. The time machine included a communication device allowing the user to call a time travel hotline, to ask for advice on interacting with the past.
Roger Hopkins worked at the hotline, which occupied the fifth floor of a large skyscraper. The job of Roger and his co-workers was to take calls from Dextron 4000 users who might have transported back to any time in the past 200 million years.
Roger came to work one Monday, and goofed off for a while until he got his first call from a time traveler.
“Dextron 4000 hotline,” said Roger. “Roger here. How can I help you?”
“I've gone back to ancient times, and I see him,” said the caller. “Jesus Christ.”
“Sir, please don't swear,” said Roger.
“Who's swearing?” said the caller. “I mean I actually see him – the real Jesus Christ.”
“You'd better be careful,” warned Roger. “There is a high risk of altering time-lines if you interact with Jesus. I strongly advise you to just discreetly snap a photo or two, and stay well clear of him.”
Later in the hour Roger got a call from a Dextron 4000 user who had transported back to the time of the dinosaurs. The caller was very excited.
“I'm here right next to a giant dinosaur, and it's awesome,” said the user. “But I have to ask you something. Those big dinosaurs with the sharp teeth and the little tiny arms – those are just the plant eaters, right? They're not carnivores, are they?”
A few seconds later Roger heard the caller screaming.
“Guess he got his answer,” said Roger, and hung up.
Roger's next caller was from a man who had transported back to the time of ancient Greece. The man bragged about how he was breaking his contract and defying all time travel rules by actually telling the ancient Greeks about advanced science and technology.
Roger started to yell at the man, reading him the riot act.
“You're in deep trouble!” hollered Roger. “You're going to mess up the time-lines!”
But then Roger's boss interrupted, and informed Roger that this user's intervention was actually part of the existing time-line. Apparently it was the underlying explanation for why the ancient Greeks were so ahead of their time – because someone in the 25th century had gone back and given them so many advanced ideas.
Later in the afternoon Roger got a call from a man named Albert who had transported himself back to Nazi Germany. Albert was determined to kill Adolf Hitler, thereby preventing the loss of millions of lives.
It was a moral dilemma for Roger. The rules were that he had to tell Albert to stop, because it would alter the existing time-lines. But how could he tell Albert not to do something that might save up to 30 million lives? Roger remembered images he had seen of all the emaciated concentration camp victims.
After agonizing over the moral dilemma, Roger told Albert: “Do what you have to do.” Roger knew that he might lose his job if anyone found out, but he couldn't bring himself to stop Albert.
Albert later called back to tell Roger that he was about to be captured by the Nazis. His assassination attempt had failed.
“You don't have any thing on you that would prove you're a time traveler, do you?” asked Roger.
“I'm carrying a wrist encyclopedia,” confessed Albert. “The kind you can use just by pressing those little buttons.”
“Damn, no!” said Roger. “This is going to mess up the time-lines in the wrong way! The Nazis will find out all kinds of stuff that will help them win the Second World War!”
Roger felt dizzy, and everything seemed to go dark. He fell unconscious. Then he woke up, and looked around him. He was shocked by what he saw.
Everything was the same in the huge room, except for three things. There was now a giant swastika flag hanging on the wall. There were large portraits of Adolf Hitler on the wall. There were three men in the room wearing the black uniform of the SS.
“Workers,” hollered one of the SS men. “Continue to provide hotline support for the time travelers of the glorious Third Reich, now in its 524th year of magnificent existence.”