Lieutenant Marla McGivers was the historian aboard the USS Enterprise, however she rarely had active duties to perform. On the few occasions when she was called to service, McGivers regarded it almost as an inconvenience, and on one occasion she even kept a landing party waiting for her arrival.

Judging from McGivers' cluttered quarters, crowded with paintings and sculpted busts, her primary pastime was art. Her favorite subjects were all strong, forceful leaders from Earth's history. McGivers' works of art depicted men such as Alexander the Great, Napoleon, Richard the Lionheart, Leif Ericson, and Flavius, a gladiator. McGivers was of the opinion that modern men did not live up to her heroes of the past.

As a historian with a fascination for bold, colorful characters, McGivers was particularly intrigued when, in 2267, the Enterprise discovered the SS Botany Bay and Khan Noonien Singh, a dictator who had ruled much of Earth in the 1990s. Though she protested that her interest in Khan was professional, she invited him to her quarters, where she began painting his portrait. She later arranged a full-dress welcome dinner in his honor, a function normally reserved for a Fleet Admiral.

When Khan pursued her, McGivers was surprised and shocked by his bullying manner, but also deeply flattered. Khan demanded absolute loyalty from her; desperately afraid of losing him, she promised to do anything he asked - including helping him in his attempts to seize the Enterprise.

Fortunately, McGivers was uncomfortable with Khan's murderous plans; she turned against him for long enough to prevent Captain Kirk's death and to help retake the ship. But it was too late to save her career.

When Kirk banished Khan and his followers to Ceti Alpha V, McGivers opted to accompany them rather than face a court-martial. Khan was pleased by her choice and dubbed her "a superior woman."

At the time that Khan's party was exiled to the planet, it was perfectly fit for Human habitation. However, a mere six months after their arrival, the neighboring planet, Ceti Alpha VI, exploded, causing an ecological disaster on Ceti Alpha V which left the planet a barren wasteland. Khan's followers struggled to survive, and the ordeal proved too much for Marla. At some point after their exile, Khan married Marla, but she was killed by a Ceti eel, the planet's only remaining indigenous lifeform. Khan was left heartbroken by the loss of his "beloved wife," and the seeds of his hatred for Kirk were sown as he swore vengeance on the captain for not checking on their progress.