Dr. Carol Marcus seems to figure rather prominently in trailers for the new movie Star Trek: Into Darkness. Why, you ask? What is her significance in the Star Trek universe? The character has made appearances a couple of times throughout the history of the show, some of which you may not have caught.

We all know that Dr. Carol Marcus is one of the scientists responsible for developing the Genesis device in Star Trek II. We also know she is Captain Kirk's old flame, and the mother of his son. That bomb was dropped on us in Star Trek II. Was that the first mention of Dr. Marcus? Not quite.

As far back as Star Trek's unprecedented second pilot, "Where No Man Has Gone Before," Captain Kirk and Gary Mitchell discuss the scientist that Kirk almost married. As a matter of fact, Mitchell states it was he who introduced them. While the name Carol Marcus is not mentioned specifically, it has been established in Star Trek lore that the reference was specifically Dr. Marcus.

So why didn't it work between Kirk and Dr. Marcus. Well, as she says in Star Trek II, "you had your world, and I had mine, and I wanted him [their son David] in mine, not chasing through the universe with his father."

In Star Trek II, Carol Marcus was played by celebrated actress, the late Bibi Besch. In Star Trek: Into Darkness, she is portrayed by Alice Eve.

So, why does the character figure so heavily in the trailer for the upcoming Star Trek movie, and what does she bring to the table?

As it turns out, including Dr. Marcus in the script does not lead to as much romance as viewers might expect. Rather, Dr. Marcus contributes to the overall action and resolution of the conflict facing our heroes. According to Chris Pine, the actor who portrays Captain Kirk, "I'll leave it to the people who watch to see how far it goes. But what she adds to it... her scientific knowledge and her education, scientifically speaking, plays a big part in helping solve the crisis."

It seems we will all have to wait until Star Trek: Into Darkness opens nationwide on May 16th to see how Dr. Carol Marcus will write her way into Star Trek history.