Writing and story

Brannon Braga envisaged "Zero Hour" as the third act in a story.

"Zero Hour" was the culmination of a season-long storyline first introduced by the events of "The Expanse", wherein an alien race called the Xindi attacks Earth and kills seven million people. During the course of the third season, the Enterprise went into the previously unexplored Delphic Expanse to search for the Xindi and to prevent a further attack which will destroy Earth.^[2] Executive producer and writer Brannon Braga felt that the end of the season in a three-part arc composed of "The Council", "Countdown" and "Zero Hour", which he compared to three acts of the same story.^[3] The episode was written by Braga alongside Rick Berman.^[4] The duo were the co-creators of Star Trek: Enterprise.^[5][6]

The idea that Enterprise would be successful in its mission was planned from the start of the development of the year-long storyline. However, the producers and writing team would joke that there would be a "bizarre twist" such as the crew returning to Earth and discovering that it was now ruled by giant cockroaches.^[3] The writers decided against a Xindi-based cliffhanger and sought an unusual twist. Braga said that "I can't remember who said 'Nazis,' but we just somehow ended up with Nazis. Then that didn't even feel like enough, so we decided to make them alien Nazis."^[3] He expected it would make the returning episode in season four "really interesting",^[3] and wanted to end the series on something "wacky".^[3] Most of the cast were not given the final few pages of the script until they were already in production.^[7] Actor Dominic Keating, who portrays Malcolm Reed on Enterprise, called the ending a "lovely twist... that just makes you scratch your head and wonder at what you've just seen."^[8] The twist was wrapped up at the start of season four with the two-part episode "Storm Front".^[9]

It was the third time that Nazis had appeared in the Star Trek franchise. The first was in the episode "Patterns of Force" in Star Trek: The Original Series, and then again on the holodeck on Star Trek: Voyager in the two-part "The Killing Game".^[3][10] In the episode, T'Pol states that "Zero Hour" takes place in 2152, a statement which contradicts other episodes. Manny Coto, executive producer and show runner for the following season, explained that this was a mistake in the script.^[11] It was later stated in the timeline published in Voyages of Imagination by Jeff Ayers that the events of "Zero Hour" took place on February 14, 2154, a day after the setting of the episode "Countdown".^[12]

Direction, filming and guest stars

Scott Bakula said initially that there were three endings for "Zero Hour", but later explained that only one was filmed.

Allan Kroeker directed the episode. He had previously directed the season two closing episode "The Expanse", and the first episode of season three, "The Xindi". Previously in the franchise, he had directed the finale of both Star Trek: Deep Space Nine and Star Trek: Voyager.^[4] Production began on March 5 and was completed eight working days later.^[4] Because there was no ability to shoot scenes using a second unit during the production of a following episode, ten pages of script were shot on the final day of filming instead of the normal seven or eight.^[13] "Zero Hour" was the final episode of Enterprise to be shot on film stock, as for the following season, the decision was made to switch to high-definition digital video.^[14]

Scott Bakula stated in an interview on The Wayne Brady Show that there were three endings to the episode filmed.^[15] This was later denied by Dominic Keating while on stage at Creation Entertainment's Grand Slam event in Pasadena in March 2004. He did clarify that the script for the final scene was delivered to his house in three envelopes, accompanied by a security guard with a dog.^[16] Bakula explained later during an online chat for the official Star Trek website that only one ending was ever filmed.^[17]

"Zero Hour" featured a guest and stunt cast larger than usual for episodes of Enterprise.^[4] For the final day of filming, there were 35 extras on set.^[16] The additional actors appearing in "Zero Hour" included J. Paul Boehmer, who portrayed an SS agent at the end of the episode. Boehmer had appeared several times previous in the Star Trek franchise, and his first part ever as an actor was as a holographic Nazi Captain in the Voyager episode "The Killing Game". He had also previously appeared in Enterprise as the Vulcan Mestral in the episode "Carbon Creek". Boehmer returned to reprise his role from "Zero Hour" during the two-part "Storm Front" in season four.^[18] Boehmer noted that the episode was filmed with a higher than normal level of secrecy, as it was the first time he did not receive a complete script and was only given his specific pages, which included warnings not to disclose anything about the episode.^[19]

In addition to the actors appearing on the episode, two members of the public made walk on appearances as Starfleet crewmen on the engineering set. These were Amy Ulen, who had won the prize on KZOK-FM.^[4] She was a high school English and drama teacher.^[20] Joining her was DJ Bob Rivers from the Seattle-based UPN affiliate radio station. Also appearing was Brian D'Arcy who gained his role through a charity auction held by Wired magazine to benefit the Starbright Foundation.^[4] Ulen would later have a cameo in the fan production Star Trek: Of Gods and Men.^[21]

Broadcast

"Zero Hour" was first broadcast on May 26, 2004, on the UPN network within the United States. It was watched by 3.91 million viewers.^[22] It received a Nielsen rating of 2.5/4 percent, which meant that it was seen by 2.5 percent of all households, and 4 percent of all households watching television at the time of the broadcast. "Zero Hour" placed UPN in fifth place in the ratings during the timeslot.^[23] The episode was first broadcast in the UK later that year on June 7, on Sky One.^[8]

Prior to the broadcast of the finale of season three, there were rumours that the series was going to be cancelled.^[16] UPN decided to renew the series, but moved it for season four to Friday nights, and so "Zero Hour" was the final episode of Enterprise to be broadcast on a Wednesday evening.^[24]

Critical response

Michelle Erica Green, in her review for TrekNation, found the ending of the episode amusing, describing it as an "insane left hook of a cliffhanger". She praised the character development elsewhere in the episode, but kept returning to what she described as "EVIL ALIEN NAZIS".^[25] Jamahl Epsicokhan, at his website Jammer's Reviews, gave the episode two and a half out of four stars. He said that the episode featured several science fiction clichés, such as having the Xindi weapon destroyed in Earth's orbit. He said that the final scene of the episode was the "Ultimate WTF ending" and compared it to the "jarring" finale of Tim Burton's version of the film Planet of the Apes.^[26] James Gray writing for The Digital Fix was positive about the episode, concluding that it was a "satisfyingly action-packed climax to the season".^[27]

IGN gave the episode 1.5 out of 5, and said "while parts of the episode had flashes of what the series should be, it was still as big a mess as the rest of Season 3." They criticized the ending of a season long plot arc with a cliffhanger.^[28] WhatCulture ranked this episode the 12th worst episode of the Star Trek franchise.^[29]

In 2021, The Digital Fix said that this episode, and preceding "Countdown", were "an exciting end to an ambitious season."^[30]