"Witness a theoretical argument, Washington, D.C., the present. Four intelligent men talking about an improbable thing like going back in time. A friendly debate revolving around a simple question: could a human being change what happened before? Interesting and theoretical, because who ever heard of a man going back in time - before tonight, that is. Because this is... the Twilight Zone."
It's April 14, 1961. Peter Corrigan and friends are discussing time travel at their men's club. Corrigan suddenly becomes dizzy. When his head clears, he has moved back to April 14, 1865 - the date of Lincoln's assassination. He tries to warn everyone at Ford's Theater, but ends up being arrested. Mr. Wellington asks that Corrigan be remanded to his custody. Wellington is actually John Wilkes Booth, and he wants no interference. He drugs Corrigan, and when he wakes up it's too late. He returns to the present, ready to tell his friends that the past really can't be changed. But he is shocked to find that William, formerly the attendant, is now rich. His great-grandfather was the only person to believe Corrigan, and made a name for himself trying to stop the assassination."Mr. Peter Corrigan, lately returned from a place 'back there,' a journey into time with highly questionable results, proving on one hand that the threads of history are woven tightly and the skein of events cannot be undone, but on the other hand there are small fragments of tapestry that can be altered. Tonight's thesis to be taken as you will, in the Twilight Zone."