Droxine was the daughter of Plasus, the high advisor of Stratos on the planet Ardana. She lived a privileged life in the cloud city above the planet's surface. She, like her father, believed the Troglytes to be inferior beings.
Droxine appeared to be quite interested in Spock, who seemed enamored with her as well, mirroring her father's earlier description of her by saying he had never met "a work of art" before. He was uncharacteristically open with her about the Vulcan mating ritual pon farr. Their conversation was interrupted by James Kirk calling for help. They found him with Vanna, a former retainer of their family, who intended to take Kirk as a hostage. It was then when Vanna revealed herself as a Disrupter. When she was taken by the guards, Droxine explained to Kirk and Spock that the Troglytes are not accustomed to light, warmth, or logic, and things were supposed to remain as they always had been.
She was present during the subsequent interrogation and torture of Vanna by Plasus, an action she explained by saying the Troglytes didn't respond to anything else.
Later, Droxine became troubled, wondering aloud to her father if the alternative solution of the filter masks might work. Her father, believing she was speaking of Kirk, forbade her to speak or think of him. Droxine clarified that it was Spock she cared for, adding that she imagined his sensitive ears would hear her if she called for him and come down to visit them. Upon hearing that Kirk had broken Vanna out of prison, Droxine defended their actions and questioned her and her father's beliefs
After the zenite had been obtained in exchange for the filter masks, Droxine told Spock that she preferred the less technical term "protectors". She then expressed her wish to not be confined in the clouds, and her desire to visit the mines of Ardana, and even Vulcan. (TOS: "The Cloud Minders")