Enterprise came around when Star Trek had been on TV continuously since 1987, with one period where there was only one series airing for the length of half a season (the start of Deep Space Nine’s third season) but otherwise two running simultaneously from 1993 to 1999. It was a glut of material, and even with one breaking radically from the mold (again, Deep Space Nine) it became easy to take the franchise for granted, and for the first time there was a sustained reaction of discontent, that in this era never really went away. Enterprise entered this fray, and attempted to have its cake and eat it, too, by being a prequel series that simultaneously looked far into the future, thanks to the story arc known as the Temporal Cold War.
Fans may have disagreed, but I loved the results.
In the first episode, “Broken Bow,” Archer must rescue a Klingon from the clutches of the Suliban, who operated at the behest of a shadowy character never officially named but quickly dubbed Future Guy by fans.
The best episode of the arc came next. The face of the Suliban, Silik, attempts to convince Archer they don’t have to be enemies, but another agent, a human from the far future named Daniels who had been masquerading as a crewman aboard the ship, presents Archer with a counterpoint. The beauty of “Cold Front” is that for a brief moment you really don’t know who to trust, capturing new levels of ambiguity that have often been the hallmark of Star Trek’s finest hours, in a franchise otherwise best known for keeping things pretty straight.
The first season ends and the second opens with “Shockwave,” which sort of mashes the ambiguity back into standard shape, hammering home that probably the whole reason the Temporal Cold War is concerning itself with Archer at all is because of his role in early Starfleet history, and the birth of the Federation itself.
The arc again leaps for greatness in its next appearance, “Future Tense,” which attempts no grand statements, but instead weaves in the Tholians (heh) and simply allows the weird possibilities of temporal shenanigans (including a clever use of repeating time that’s saved as a side element of the plot) to enjoy the spotlight, Archer being frustrated that he has no control of any of it (a metaphor apt for the whole series).
Then the Xindi arc happens and in the third season Daniels again pops up to emphasize Archer’s big future, and in “Carpenter Street” helps him out with a little bit of contemporary time travel (with emphasis on pizza! and Jeffrey Dean Morgan suffering under heavy latex).
The producers got the message that fans weren’t having it, so the fourth season wraps up involvement in the Temporal Cold War with “Storm Front,” which naturally revolves around time travel and Nazis. I always liked to speculate that the head alien Nazi was in fact Future Guy (speculation had always hinged on a Romulan, admittedly). And then the series ends at the end of the season anyway.