"E²" (pronounced "E-Squared" used against him. Lorian reveals that he had a chance to stop the Xindi Probe from The Expanse from attacking Earth by sacrificing Enterprise, but failed because he hesitated to condemn his crew. The two captains finally agree to work towards their shared mission. Meanwhile, T'Pol meets her older self and discuss her addiction to Trelium-D and her relationship with Tucker. The older T'Pol confirms the younger's deepest fears: in Tucker, there is something bringing irrationality into her life which she can not control, but which will nurture her and have a positive irreplaceable effect on her life and spirit.
The Enterprises enter the nebula and Archer's is quickly disabled. Lorian's then tows it into the corridor using a tractor beam and turns back to attack the Kovaalan ships, saying he will follow shortly. Archer's Enterprise arrives safely, but old Enterprise never emerges and Archer wonders if, by successfully traversing the corridor, they ceased to exist. Degra arrives for their rendezvous.
Production
thumb|[[Roxann Dawson directed this episode. In addition to directing several Star Trek episodes, she starred as B'Elanna Torres on Star Trek: Voyager]]
The episode was the fifth written by Mike Sussman in the third season. His previous work was "Hatchery", co-written with André Bormanis. It was also the fourth episode of the season directed by Roxann Dawson. With "E²", she had directed more episodes than any other director at that point in the season, having previously worked on "Doctor's Orders", "Exile" and "Chosen Realm". Scott Bakula commented on the production of the episode: "...a great episode along the lines of 'Twilight' and 'Similitude.' It's a classic sci-fi and Star Trek episode."
Filming began on February 3, 2004, overlapping with the final day of production on the previous episode, "The Forgotten". Production required the use of the standing Enterprise sets, as well as those that represented Degra's ship. The majority of the shoot was completed on February 11, but an additional day of special effects filming with part of the cast also took place on February 13, 2004. The actors who played the members of the Xindi Council were among the guest stars who appeared in this episode: Randy Oglesby; Rick Worthy; and Tucker Smallwood. In addition, a number of guest actors appeared in Star Trek for the first time: David Andrews; Tess Lina; Tom Schanley; and Steve Truitt. Compared to other shows in the same time slot, it placed sixth on the night, one place behind Smallville on The WB.
Michelle Erica Green reviewed the episode for TrekNation, saying that it "focused far more on the characters and the consequences of their contact with their descendants than it is on the vast technobabble resulting in a successful traverse of the Xindi corridor." She praised David Andrews as Lorian, calling it "a wonderful bit of casting," and felt that the character's actions mirrored those of Captain Archer previously in the series. She compared the resolution of "E²" to the Star Trek: Voyager episode "Deadlock" and the series finale of Star Trek: The Next Generation, "All Good Things...". She felt that the lack of conclusion to what happened to the future Enterprise was "very satisfying." Jamahl Epsicokhan on his website Jammer's Reviews, called the episode an "acceptable but all-too-familiar time-travel concept," and a "step down" compared to the previous three episodes of the series. He compared it to the Star Trek: Deep Space Nine episode "Children of Time", which he said "was a far superior episode because it was about our characters – astonishingly and agonizingly – choosing one destiny over another, and sacrificing a great deal in coming to that decision." He gave "E²" a rating of two and a half out of four.
Den of Geek ranked "E²" as the seventh best episode of Enterprise. The Hollywood Reporter rated it as 92nd best episode of all Star Trek up to that time, calling it a "fine episode". The Hollywood Reporter also interviewed various cast and production crew of the Star Trek franchise to determine the "100 Greatest Episodes" from across the five series, ranking "E²" as the 92nd best episode of all time.
Home media release
The first home media release of "E²" was as part of the season three DVD box set, released in the United States on September 27, 2005. It subsequently became one of three Enterprise episodes to be included in the Star Trek: Alternative Realities Collective DVD set which was released in 2009. The other episodes were "In a Mirror, Darkly" and "Twilight", and also featured were other mirror universe installments including "Mirror, Mirror" and three of those from Deep Space Nine. The Blu-ray release of Enterprise was announced in early 2013, and released on January 7, 2014. This also featured deleted scenes from this episode.
See also
- E (mathematical constant)