When an accident causes Dr. McCoy to go temporarily insane, he escapes to a strange planet. There, the search party discovers a device left by a superior, vanished civilization, a time portal that plays the history of Earth for them - but then Bones jumps through it into the past, causing a change in history important enough to make the Enterprise vanish. Kirk and Spock, who fortunately made a tricorder recording, must attempt to go through to just before McCoy's arrival and stop him from changing history in the United States during the Great Depression, where they have no advanced technology available. Written by
Did You Know?
Spock picks a combination lock to obtain tools. This type of single-dial combination padlock was first marketed by Master Lock in 1935, five years after the events of the episode, and the early models had a metal dial, with the plastic dial depicted on the show coming at least two decades later. The particular lock Spock picks appears to be a much later copy of the Master design, possibly from the late 1950s, but much more likely to be from the early to mid 1960s, which was when the show was filmed. See more
[having stepped into Earth's past
We seem to be costumed a little out of step with the time.
I'm afraid I'm going to be difficult to explain in any case, Captain.
Well, Mr. Spock, I... if we can't disguise you, we'll find some way of... explaining you.
That should prove interesting.
The closing credits are set against a combination background of stills from that episode and previous episodes. See more
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Theme From Star Trek
Written by Alexander Courage See more