SPOILERS for Star Trek: Discovery Episode 6, “Lethe,” follow.
Fans knew going into Star Trek: Discovery that the series would have a strong connection to Leonard Nimoy’s popular Vulcan from The Original Series. After all, James Frain was cast early on as Spock’s father, Sarek, and Sonequa Martin-Green’s lead character, Michael Burnham, was eventually revealed to be Spock’s surrogate sister.
However, up until now, Spock has only existed on the periphery. The closest Discovery has come to mentioning Spock by name is Burnham remembering how Amanda Grayson, Sarek’s wife, used to read Lewis Carroll stories to both her and to her mother’s son, which would be Spock.
Spock’s first mention on Discovery came during a kind of flashback scene. The episode “Lethe” involved Burnham realizing that Sarek’s life was in danger when she felt his pain through the Katra bond that he created with her in order to save her life following an attempted assassination by Vulcan extremists, the same Vulcan extremists trying to kill Sarek now.
In order to locate Sarek, Burnham – with the help of her Discovery crewmates – had to travel back through that Katra bond to reconnect with Sarek. This brought her into the memory that was replaying in Sarek’s mind as he lay at death’s door, that of the day he, Amanda, and Burnham learned that Burnham had not been accepted into the Vulcan Expeditionary Group.
Sarek acted unexpectedly hostile towards Burnham when he discovered that his daughter was entering his mind. He used his own mental strength to expel Burnham from his mind.
However, repeat visits to this memory eventually compelled Sarek to admit he had not revealed the truth to Burnham. Sarek received the news of Burnham’s rejection in a private conversation and delivered the news himself to Amanda and Michael, but left one important part out.
What Sarek left out of what he told Michael was that the Vulcan Expeditionary Group was willing to accept her, or to accept her surrogate brother, but not both. Sarek was told that integration of humans into Vulcan culture needed to be slow and gradual and that having both of Sarek’s human children, despite Spock being only half-human, join the group would be pushing it too far too fast.
Sarek was forced to choose between allowing Burnham, who was ready then, or Spock, who was still studying, to join the Vulcan Expeditionary Group. Sarek chose his own blood and delivered the bad news, carefully edited, to Burnham only for Spock to later chose to join Starfleet over joining the Vulcan Expeditionary Force.
This new information shines an entirely new light on what fans have known about Spock’s relationship with Sarek. Fans knew that Sarek broke off his relationship Spock after Spock decided to enroll in Starfleet Academy against his father’s wishes. Up until now, the reason for this was believed to be entirely about Sarek being bitter that Spock did not follow in his father’s footsteps the same way Sarek had followed in his father's footsteps.
However, we now know that Sarek denied Burnham, his other child, her dream of joining the Vulcan Expeditionary Group only for Spock, his own flesh and blood, to cast the opportunity aside, which means Spock's decision may have deepened the feelings of shame that Sarek revealed to Burnham in this episode of Discovery. In the end, just like Sarek’s fixation on this memory was more about his own failings than that of his surrogate daughter, so too may his estrangement from Spock be more about Sarek’s own regrets than the choices of his son.
New Star Trek: Discovery episodes become available to stream Sundays at 8:30 p.m ET on CBS All Access.