Beamed up during an ion storm, which causes a transporter malfunction, the landing party of Kirk, McCoy, Scotty and Uhura find themselves in a mirror universe aboard a parallel Enterprise run by ruthless barbarians. The ion storm also caused their malicious counterparts to beam to the real starship. Kirk and the others must find a way home before they are discovered and exposed by their parallel crew members, who use treachery, back-stabbing and seduction to get what they want. Written by
Did You Know?
In the mirror universe, the male computer explains that James Kirk became Captain by murdering his predecessor Christopher Pike, a character played in previous installments by Jeffrey Hunter
and Sean Kenney
. This is possibly the only time in TOS where Pike is mentioned but does not appear. See more
When the landing party is in the middle of the cross-universe transfer, the USS/ISS Enterprise is seen in orbit going in opposite directions (USS Enterprise going counterclockwise [when viewed from above]; ISS Enterprise going clockwise). However, through the rest of this episode, the ISS Enterprise is going counterclockwise. See more
I'm a doctor, NOT an engineer.
NOW you're an engineer.