One of the highlights of Star Trek's Kelvin Timeline is the cast, as the actors have taken iconic roles and made them their own over the course of three films. The ensemble has tremendous chemistry with one another, which makes the U.S.S. Enterprise crew feel like a fully formed family. At the end of 2013's Star Trek Into Darkness, it appeared that the group had a new member in Carol Marcus (Alice Eve), who was on the ship as it began its five year mission through deep space.
Star Trek Beyond picks up about three years into that assignment, and oddly enough, Marcus is nowhere to be seen. The character isn't even mentioned by name throughout the entire running time, making it seem like the creative team had just forgotten about her completely. But this is not the case, as co-writer Simon Pegg has now provided an explanation for Carol's absence in the threequel.
On an episode of the Star Trek podcast, Pegg was asked about not including Carol in Beyond. Apparently, he and Doug Jung could not find a way to have her play a meaningful role in the story and decided it would be better to drop her completely than run the risk of "underserving" the character:
“We thought rather than have Carol Marcus be not used to a reasonable capacity, let’s just not include her, have her be alive, in canon, and be ready to come back at any time.”
Pegg went on to say that they attempted to provide an in-universe reason for Marcus not being there, such as having her work on the Genesis project. However, these were just in initial drafts of the screenplay and obviously did not make the final cut. It will be interesting to see if Carol returns for the recently announced Star Trek 4, since the conclusion of Beyond suggests Sofia Boutella's Jaylah, now in Starfleet Academy, could join the group for their next adventure through the Final Frontier. Fans may have seen the last of Dr. Marcus on the big screen.
In retrospect, it's probably for the best that Marcus wasn't in Beyond. Other than being just another part of the Enterprise crew (of which there are already seven main players), it's difficult to see how Carol could have fit naturally into the narrative. For Into Darkness, her connection with Admiral Marcus (Peter Weller) served as a key emotional element, but she arguably wouldn't have had much to contribute to Beyond. Additionally, the film introduces new characters like Jaylah and Krall (Idris Elba), and it was necessary for those individuals to be well-developed so they made a strong impact with viewers. In a two hour movie, there isn't always enough screen time to go around and tough choices have to be made.
Some viewers were probably confused by Marcus not being in Beyond, but Pegg, Jung, and director Justin Lin seemed to have done the best they could. Though the film is having an uphill climb at the box office, it received positive reviews across the board, with many praising it as a fun blockbuster that honored the Star Trek legacy. As long as the movies keep Kirk, Spock, Bones, and the rest of the primary crew together, there won't be too many complaints. Franchises have a history of rotating supporting casts with little-to-no explanation, and this is no different.
Star Trek Beyond is now playing in U.S. theaters.
Source: Star Trek Podcast