Spock's (Leonard Nimoy) romance in the Star Trek: The Original Series season 3's episode, "The Enterprise Incident," helps explain his dream of Vulcan and Romulan unification. Spock, Captain James T. Kirk (William Shatner), and the crew of the USS Enterprise saw Romulans for the first time in the TOS season 1 episode, "Balance of Terror," and learned Romulans are offshoots of Spock's Vulcan race. But Spock's next major encounter with the Romulans could be the determining factor of his 24th-century quest to unify the Vulcan and Romulan people.

In Star Trek: The Next Generation's classic two-parter, "Unification," Ambassador Spock works covertly on Romulus to bring about peace between Vulcans and Romulans. Starfleet believes Spock has turned on the United Federation of Planets and dispatches Captain Jean-Luc Picard (Patrick Stewart) to investigate. Picard learned the truth and left Spock to his important work, but the heroic Vulcan never achieved his dream. J.J. Abrams' Star Trek 2009 revealed that Spock attempted to save Romulus from its sun going supernova, but he was instead banished back in time and sent to an alternate timeline created by the Romulan Nero (Eric Bana). Ambassador Spock ultimately never returned to his original timeline, and he died in the Kelvin reality prior to Star Trek Beyond.

Spock’s TOS “Enterprise Incident” Set Up His TNG Vulcan & Romulan Dream

Spock TOS Romulan Commander

Star Trek: The Original Series season 3's "The Enterprise Incident" offers a window into why Vulcan and Romulan unification became so important to Spock. Captain Kirk and his Vulcan Science Officer engaged in a clandestine mission to steal a Romulan cloaking device. As part of the ruse, Kirk feigned insanity while Spock pretended to be a turncoat. Taking advantage of the attraction the Romulan Commander (Joanne Linville) felt for him, Spock pretended to reciprocate as he and Kirk heisted the cloak. The Romulan Commander was even taken prisoner by Starfleet at the conclusion of their successful gambit.

However, Spock may have felt more for the Romulan Commander than he let on. Spock is half-human, after all, and the Romulan Commander was sincere in her romantic interest. Perhaps this incident left a deep regret within Spock. Coupled by the racism hurled at Spock in "Balance of Terror" when it was discovered Romulans and Vulcans had a common ancestry, the Science Officer could have sparked the desire to see the two cousin races reunited. Certainly, a unified Vulcan and Romulus would have allowed Spock and the Romulan Commander to be together without their worlds' opposing politics standing between them.

Spock Never Lived To See Star Trek: Discovery Fulfill His Vulcan & Romulan Dream

Spock Burnham Discovery season 3

Following Spock's diplomatic success in helping to establish peace between the Federation and the Klingons in Star Trek VI: The Undiscovered Country, Spock left Starfleet to become an Ambassador. When, exactly, Spock began working toward Vulcan and Romulan unification isn't clear, but he was deep into it by Star Trek: The Next Generation's late 24th century. However, Spock's dream would elude him, and he never saw the fulfillment of Vulcan and Romulan unification. But it did happen centuries after Spock's death.

Star Trek: Discovery season 3 established that Vulcans and Romulans share the Vulcan homeworld, renamed Ni'Var, in the 32nd century. Spock's adopted sister, Commander Michael Burnham (Sonequa Martin-Green), learned about Spock's work on Romulus and how he jumpstarted what ultimately became Ni'Var. However, even if Burnham learned all she could about Spock from official Starfleet records, she would never know the truth about Spock's encounter with the Romulan Commander in Star Trek: The Original Series' "The Enterprise Incident" and the deciding impact it may have had toward Spock's desire to bring Vulcans and Romulans together.