Star Trek: Strange New Worlds Season 4 Finale Has A Hilarious Deep Space Nine Easter Egg For Serious Fans

Did you know that there's so much time travel in "Star Trek" that there's an in-universe Department of Temporal Investigations? It first showed up on "Star Trek: Deep Space Nine." Did you know that Nurse Chapel dated someone from that department? Trekkies watching the Season 4 finale of "Star Trek: Strange New Worlds" will light up when Nurse Chapel (Jess Bush) makes a throw-away reference to it.

The episode, "Tomorrow's Enterprise," is a fun time-travel plot that sees Uhura (Celia Rose Gooding) communicating with a one-year-hence future version of herself via a swirling space portal. In the future, Uhura is more assured and confident, but is also emotionally smarting from the death of her boyfriend, Scotty (Martin Quinn), from a year earlier. In the present, Uhura learns that Scotty will die very soon, causing the two Uhuras to begin investigating the circumstances of his death and working to prevent it. In a further twist, the two Uhuras also eventually transpose, occupying each other's timelines. 

Partway through the episode, Kirk (Paul Welsey) — from the future timeline — senses that something is fishy with Uhura, as she suddenly looks and dresses like she did a year ago. Kirk pulls Uhura aside to interrogate her, and Uhura confesses that, yes, she's a time traveler from a year in the past. Nurse Chapel enters the room to aid Kirk, hears that her crewmate is a time-traveler, and gives her throw-away line about having dated a woman from the Department of Temporal Investigations. The woman, Chapel says, was a little nuts. Which is no wonder. In the "Star Trek" timeline, the Department of Temporal Investigations is very secret and may not have been invented yet. 

In the "Star Trek: Strange New Worlds" episode "Tomorrow and Tomorrow and Tomorrow," La'an (Christina Chong) is confronted by a character who tells her that she, as a denizen of the 23rd century, might not yet have heard of the Department of Temporal Investigations (DTI), as it hadn't been formed yet. We've previously written about the DTI as one of Starfleet's most mysterious organizations.

The DTI played a major role in the 24th-century set series "Star Trek: Deep Space Nine," specifically in the episode "Trials and Tribble-ations." In that episode, two DTI agents visit Captain Sisko (Avery Brooks) about a time-travel incident they were savvy to. Sisko and several members of his crew had recently traveled back in time to the events of the original "Star Trek" episode "The Trouble with Tribbles," and interacted with the likes of Captain Kirk (William Shatner) and other familiar faces. (Fun trivia: Tribbles almost had a much cuter name.) The makers of the episode used state-of-the-art digital effects and clever editing to insert the "Deep Space Nine" characters into an original "Star Trek" episode, and it's all very entertaining. 

When Sisko mentions Kirk's name, the DTI agents both roll their eyes. The DTI is wearisomely familiar with Kirk, and they note that Kirk had committed at least 17 time travel violations during his tenure with Starfleet (and even non-Trekkies can likely think of a few off the top of their heads). The episode gives the impression that the DTI is very strict and humorless, and they take all time-travel-related violations very seriously indeed. On "Star Trek," mucking about with history is strictly verboten, and the current timeline needs to be retained as-is. Causality is too unpredictable to allow for anything else. 

In "Tomorrow and Tomorrow and Tomorrow," the DTI had to prevent a time-traveling Romulan assassin from killing a future tyrant when the tyrant was still a child. That answers the immediate ethical conundrum you were about to mention: No, no one in "Star Trek" is allowed to go back in time and assassinate Hitler. While that may seem like a good idea on the surface, the DTI knows that doing so might unleash a skewed version of human history that ends up even worse. 

Elsewhere, since the comedic animated series "Star Trek: Lower Decks" is so chock-full of "Trek" references, you can bet that the DTI would be mentioned at least once. On that show, Boimler (Jack Quaid) is assigned to the shadowy Division 14 and he thinks for a moment that it's "the time travel police." 

The DTI is also mentioned at the end of the first season of the lovely "Star Trek: Prodigy," which sports a time travel story of its own. Admiral Jellico (Ronny Cox) has ordered Admiral Janeway (Kate Mulgrew) to locate and seize the USS Protostar, the show's central vessel, and they had some time travel-related plans for it. The DTI was to send the ship back in time, and the department was indeed mentioned by name.

When Nurse Chapel mentions that she had a girlfriend claiming to be from the DTI, of course the girlfriend would sound like a kook. The DTI didn't exist yet on "SNW." So it is confirmed, in "Star Trek" canon, that Nurse Chapel dated a woman who came from the future.