Star Trek: 10 Story Arcs You Can Binge In A Day
4. The USS Defiant's Journey
The Episodes:
TOS: "The Tholian Web"
Enterprise: "In a Mirror, Darkly", "In a Mirror, Darkly, Part II"
Discovery: "Despite Yourself", "The Wolf Inside"
The Background:
The other USS Defiant.
Initially a one-off, the Defiant appeared in the TOS episode "The Tholian Web" in which it slipped into an interphasic rift and disappeared. Some 37 years later (real time), the Star Trek franchise revisited the Defiant in the Star Trek: Enterprise two-parter "In a Mirror Darkly" which revealed the ship had found its way into the past and into the Mirror Universe.
The fate of the Defiant would go on to be a pivotal plot point when the USS Discovery also found itself in the Mirror Universe in "Despite Yourself" and "The Wolf Inside".