4-18: In a Mirror, Darkly
In the mirror universe, a radically different Enterprise crew searches for the technologically-superior U.S.S Defiant, trapped from our universe.
The Enterprise assists Emory Erickson, the inventory of the transporter, who is secretly trying to save his long-lost son.
4-01: Storm Front, Part I
Trapped in Earth during World War II, Enterprise investigates dramatic changes in the timeline as a result of the Temporal Cold War.