Prof. Joseph Fitzgerald talks with one of his students, about a paper the student would like to write - a paper on the speech President Kennedy will be giving that day at the Trade Mart in Dallas, Texas.
Prof. Kennedy goes into his office, and walks to his desk. He takes something out of his pocket, and a coin falls on the desk...
a coin with the profile of President Kennedy.
He hears a buzzing, whirring noise, and looks around the empty office.
A figure begins to materialize.
The professor addresses the figure as Kate. She is a close friend and an employee in the historian-concern that the Professor also works for. They have perfected time travel, and the Professor is studying the Kennedy presidency. Kate had last checked in with him 2 hours ago her time, but it's been several months in his timeline.
The Professor had dropped the 50 cent piece on his desk...
and she picks it up. It's a 1964 Kennedy half dollar. Highly illegal in 1963, the year the Professor is in, and when Kennedy is still alive. She takes him to task on it as a breach of history protocol, which he says is not strictly enforced. He says that she has to allow him his own kind of hero worship.
She wished him well, opens the wrist device that handles the actual time travel, and taps in an order.
As she begins to disappear, she says a few words in Chinese. He doesn't quite hear her, but figures he can ask her when he sees her again.
Professor Fitzgerald uses his wrist device to coordinate a camera...
and his ring, which if separated from wrist device will send the ring wearer back to point of departure - the future.
His journey to Dallas is nearly instantanous.
The Professor turns on his camera and begins to photograph the cavalcade as it turns into Dealey Plaza.
The Secret Service are on a car behind the President.
The Professor aims his camera at the 6th floor of the Texas Book Depository...
and sees the gun pointing toward the President.
Whether he panics, or whether he truly was trying to change history, Professor Fitzgerald begins yelling, warning the President and the Secret Service that he was about to be shot.
He succeeds in alerting the agents, who swarm all over the President's car and the Professor himself. The President is safe.
The Professor is taken to the Dallas airport by the Secret Service, to meet the President.
The President thanks him, and tells the Professor he's read some of his papers. He asks if they are related, because of his last name, Fitzgerald, but the Professor says he doesn't think so.
At that moment, Vice President Johnson arrives and says that he has to excuse himself. Several tornadoes had suddenly touched down in Texas, and he was going to stay to see what he could do.
The Professor seems to feel that the tornadoes mean something bad, but says nothing. The President invites him to come to Washington, and he gladly accepts.
On Air Force One, Kennedy and Fitzgerald talk about the press and the fun Kennedy has sparring with them.
Fitzgerald drops the Kennedy half dollar, and the Secret Service agent picks it up. Fitzgerald tries to act nonchalant, but the agent is now vaguely suspicious of the Professor, and in possession of this highly illegal coin.
The President gets some news from an aide, and looks grave. Fitzgerald asks what has happened. The President tells him that Soviet forces have captured West Berlin. Fitzgerald says that Kruschev would never do that. Kennedy says that Premier Kruschev was assassinated this afternoon.
Now Fitzgerald is really starting to look worried. He knows, though we don't yet, that this is because of his actions in stopping the assassination.
Back at the White House, Kennedy says that due to security, Fitzgerald will have to stay the night.

Fitzgerald tells the agent, Ray, that he's left his camera on the plane. Ray tells him not to worry, they'll get it back to the White House before he leaves tomorrow.
In his room, Fitzgerald talks to his wrist device.
Apparently his act of saving President Kennedy has resulted in a severe rift in the fabric of time. He runs through what options he has, but there are none. All options result in the complete eradication of life on the planet. To save the world, the Kennedy presidency must end as it originally did. With his death.
 
 
The President is dealing with a plane flying over Russia, that has been fired at. He tells the pilot to defend himself.
Ray has taken the half dollar to someone at the Mint. He says they have nothing like this in development, since it's against policy to put a living president on money. They wonder if it's a joke set up by the President's brothers, but Ray is now even more suspicious of the Professor.
He takes the coin and the camera to the President, telling him about the alloy of the camera being totally foreign to the lab, and that they can't figure out how to make it work. The President summons Fitzgerald. He asks him about the coin. Fitzgerald says the coin has been in his family for over 200 years. The President does not believe him.
Fitzgerald picks up the camera to show him...
turning it on and projecting what he took pictures of yesterday into thin air. Both the President and Ray are stunned.
Fitzgerald says that he can show them tapes of other eras and timelines, if they need further convincing.
The President can't help but believe it, and he asks again if they are related. Fitzgerald smiles and says that they are. He is one of Kennedy's descendants.
He asks why the Professor chose this time to contact him. To study how he reacted to the Berlin crisis? Fitzgerald says he didn't know about the Berlin crisis. The President puts all the clues together, remembering the 1964 coin, and realizes that he should have died during the assassination attempt that day.
Fitzgerald says that because of his actions, the fabric of time has been ripped beyond repair. Kennedy asks what can be done. Fitzgerald hangs his head, and Kennedy knows what that means. He has to go back to Dallas. He says he's ready to go.
Fitzgerald turns around, to start the time-travel process, then remembers the ring on his finger.
Ray asks to take the President's place, but Kennedy tells him it's his boat. Fitzgerald hands the ring to the President and tells him to put it on.
The President disappears, and Ray gets nervous, wondering what is happening.
"You swore an oath to protect the President, didn't you? We going back, but first I need to make a few changes."
Later, at Parkland Hospital...
we find Fitzgerald's friend from the future is a doctor at the hospital. She and Ray talk about what has happened; he recognized the time-traveling ring she wears. She says Fitzgerald never knew his destiny - no man ever does. But she did, since she was also investigating in the past.
She couldn't tell him what she knew, the last time she saw him. All she could say was the few words in Chinese, "Farewell, old friend, farewell."
Ray asks if his memories will change the past. She says no, because they didn't.
The half dollar is now history.
In a classroom in the future...
John F. Kennedy is safe, thanks to the sacrifice of his descendant, teaching and inspiring another generation.