Star Trek: 12 Best Alternate Reality Episodes

To date, this remains the only episode of Star Trek to be set in the Mirror Universe from start to finish and not feature any of the main recurring characters. This is one of the most fun two parters in Star Trek's history, while also serving as a surprising sequel to The Tholian Web.

The ISS Enterprise is captained by the fearsome Captain Forrest, played by frequent Trek actor Vaughan Armstrong. They become aware of a ship that has been taken by the Tholians - one that turns out to be the USS Defiant NCC-1764, the ship that was taken in the Original Series The Tholian Web.

The episode is another in the great tradition of having the crew get to play vile and unpleasant versions of themselves, for the most part. It also shows the beginnings of the Vulcans' attempts to gain a stronger position of power within the Terran Empire, with both T'pol and Soval trying to oust several of their oppressors.

The episodes are worth watching to see the Defiant carving its way through the older technology alone, while the '60s aesthetic is kept for both continuity and hilarity. In recent times, Star Trek has come under a lot of fire for seemingly stepping away from established canon with Discovery. This episode shows that, while fun and beautiful, the '60s sets really do not hold up well, compared to the more modern tech.

That, however is not the point of In A Mirror, Darkly. The point is for everyone to have as much fun as possible - and they nail it.