Two men lost in time as a result of a government project have to save the project from a saboteur and then deal with aliens invading earth in the late nineteenth century.
"The Time Tunnel" was Irwin Allen's third attempt at a TV series; unlike his first two, this one wasn't a success and only lasted one season. As such, it became one of those series with insufficient episodes to allow for effective syndication, and thus became fodder for jury-rigged TV movies made by slapping two episodes together.
Now this one I remember catching occasionally as a kid. I didn't watch it much; outside of the time tunnel itself, the show didn't have much science fiction content and largely seemed satisfied to place our time travellers in various historical situations; in this way, the show was a little bit like early 'Doctor Who'. This movie, however, concentrated on some of the episodes with a greater degree of fantastic content; it combines bits of the first episode "Rendezvous with Yesterday" to serve as story background, and then we get the two episodes "Chase Through Time" and "Visitors from Beyond the Stars", the first of which involves a trip into the far future where man has evolved into a sort of beelike existence and then a trip to the prehistoric days where slurpasaurs wrestle. The second one involves an alien invasion.
As usual with Irwin Allen, the science fiction eye candy is the main attraction; in particular, the time tunnel itself is memorable. It's also fun to spot familiar faces; Whit Bissell and Lee Meriwether were regulars, and Robert Duvall and John Hoyt pop up in the various segments. The stories themselves are fairly simplistic, and the two leads are fairly bland, and it's all pretty silly if you think about it; for example, the spy who sets the timer for the nuclear bomb could have chosen to hide it somewhere where he wouldn't attract attention to himself by having to attack someone, but for some reason he chooses to handle it the way he does. It's watchable enough, but it does remind you how much more sophisticated some other science fiction series were.