Her ancestors were part of a wave of multi-generational starships dispatched to nearby galaxies to find new territories for the Empire to conquer and occupy. Reaching the Milky Way Galaxy after centuries in the intergalactic void, her ship was destroyed crossing the galactic barrier. Under Rojan's command, Drea escaped with three other crewmembers in a life-craft to a Class M planet. The Kelvans adopted humanoid forms more compatible with the new region's intelligent life and available transportation.
After a false distress call attracted the attention of Captain James T. Kirk, Drea was part of the boarding party that captured the USS Enterprise. Drea served as the Enterprise flight officer for the return home to report their discoveries to the Kelvan Empire.
Humanoid sense perceptions and emotional tendencies were alien to Kelvan experience, allowing Kirk and his senior officers to exploit Kelvan weaknesses. Drea was the only Kelvan not subjected to this attempted subversion. Eventually, Kirk suggested that the Kelvans' new Humanity could be fully realized on a planet in the Milky Way, and the Kelvans restored control of the Enterprise to Kirk and his crew. (TOS: "By Any Other Name")