The Enterprise is transporting its first captain, Robert April, to Babel where he will reluctantly accept his retirement. When the Enterprise attempts to stop an unidentified vessel on a collision course with the Beta Niobe nova, the ship accidentally passes 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 becomes unable to man the consoles.
The TV Archaeologist
Did You Know?
Kirk mentions that there are 430 people aboard the Enterprise, as in Star Trek: The Original Series
. Under the economy of drawing the animated series (or hiring extras in the original), the viewer rarely, if ever, has a sense that there are more than 15 or 20 people on board. See more
Captain, the flower is not the only thing on board that is growing younger.
Ship's chronometers are also running backward. The flow of time is reversed in this universe. The longer we stay here, the younger we will become.