The Enterprise is transporting its first Captain, Robert April to Babel, where he will reluctantly accept his retirement. When the Enterprise attempt to stop an unidentified vessel on a collision course with the Beta Niobe nova, the ship accidentally pass into an alternate dimension, where time flows in the opposite direction. The crew of the Enterprise rapidly begins to grow younger in age, and soon become unable to man the consoles.
The TV Archaeologist
Did You Know?
This was the last "Star Trek" production until Star Trek: The Motion Picture
(1979) five years later. This is the longest period of time in which the franchise lay dormant. See more
No reason is given as to why the crew de-age so quickly. They were only in the negative universe a few days at most. While they would de-age, it would not even be noticeable. They certainly would not have become children. See more
Gentlemen, I'm sure none of us mind growing younger instead of older for a change.
Commodore Robert April
It pleases me, Jim. If we stay here long enough I'll no longer be at the mandatory retirement age.
References Star Trek: Friday's Child