Have you checked out the new TV series TIMELESS? So far, three episodes have aired. The intended appeal to the audience, I suppose, is that the characters visit a different point in history every week and have breathtaking adventures. The premise: The antagonist, Flynn, has stolen the prototype time machine for the purpose of changing the past—why, we don't know yet. The three heroes—a female history professor (devoted primarily to preserving the timeline as we know it), a soldier (tasked mainly with eliminating Flynn), and the engineer who's the main inventor of the time machine—pursue Flynn in a second time machine that fortunately happens to be available. The jumping to different dates in the past recalls QUANTUM LEAP, which is credited as one of the inspirations for TIMELESS. The heroes' chasing after a villain in a time machine brings to mind the movie TIME AFTER TIME, in which H. G. Wells travels to our present to catch Jack the Ripper.
What I like about the series so far is that it makes some serious attempt to deal with the risks of changing history. In QUANTUM LEAP, Sam usually had to "set right what once went wrong" in the lives of individuals, not on a broader historical level. One exception was his interference in Kennedy's assassination. From the audience's viewpoint, Sam failed; JFK still died. In the universe of the TV program, however, Sam at least succeeded in saving Jackie Kennedy, slain in their original timeline. In TIMELESS, the first three episodes take the heroes to the Hindenburg disaster, the assassination of Lincoln, and a day in 1962 in Las Vegas, where Flynn plots to steal the core of a nuclear weapon from the nearby atomic testing facility. Because one of the Hindenburg passengers who should have died survives, the history professor's ancestry changes; she returns to the present to find her dying mother in perfect health—but her sister erased from existence. In the nineteenth century, she fights the temptation to try preventing Lincoln's death. History does change, though, in that John Wilkes Booth doesn't kill the President; Flynn does. You'd think the murder of Lincoln by an unidentified assassin with an unknown model of gun would leave a conspicuous trace on the timeline, but no change in the status of the twenty-first century is mentioned when the heroes return to the present. So the show's attention to problems of altering history is selective—not surprisingly, since their main objective is suspenseful entertainment, not cerebral SF. Still, it will be interesting to see how they grapple with such problems in the future. The history professor wants to protect the timeline. The soldier wants only to eliminate the threat of Flynn by any means necessary. As for the African American inventor/pilot of the time machine, if left to his own devices he would try to change history for the better in some cases (he was in favor of saving Lincoln).
It appears that each episode will pose its own challenge for the heroes—thwarting whatever Flynn's goal for that particular visit to the past—and meanwhile contribute to the solution of the long-term story arc problem: Why is Flynn trying to change the timeline? So far, we've had only cryptic hints. What disaster could he be trying to prevent that would justify wreaking havoc on history as we know it?
The history professor plays the role held by the generic "scientist" in many TV programs and movies. Any scientist (e.g. the Professor on GILLIGAN'S ISLAND, the type TVTropes.org calls the Omnidisciplinary Scientist) is assumed for story purposes to have expertise in any field the plot requires, regardless of his nominal specialty. I'm not sure whether TIMELESS has mentioned what historical era the professor in this series specializes in, but she seems to know everything about every date they've landed in so far. And it's not as if the time travelers get long periods of respite between trips to do research. She even knows the name of one of Kennedy's mistresses who acted as a liaison between JFK and the Mafia in 1962. The audience just has to suspend disbelief in the breadth of the character's knowledge and go along for the ride (so to speak).
For a thrilling, ingenious story of an attempt to "fix" the past that makes things much worse, read Stephen King's 11-22-63, his novel about a time traveler trying to stop Kennedy's assassination. This book's theory of time travel has a twist I've never seen anywhere else: Every trip back through the portal (no matter who does it) resets the past to the default timeline. Pro, you can keep trying until you get it right; con, you have to start from scratch with every foray.
Margaret L. CarterCarter's Crypt