As an educated professional on Makon III, Jeena was a second-class citizen and considered property. When President Wan'Brek approved a plan to develop warp drive, secretary of affairs Dol'Rum purchased Jeena along with other scientists and engineers who would be needed for the project. She invented a warp reactor decades ahead of schedule. In her design, EPS regulators sent more drive plasma through the injectors than in a Starfleet reactor.
After landing, she and her pilot, fellow scientist Pipp, were approached by a delegation from the Federation starship USS Enterprise which had detected the warp flight, but because they were practically slaves, they were not entitled to reply. Instead, Jeena, Pipp and their development team were confined by Wan'Brek. Realizing that Captain James T. Kirk had addressed her as an equal, she managed to escape her holding cell, draw his attention, and was beamed up. She was given a tour of the Enterprise — she visited engineering and discussed warp theory with Montgomery Scott. She spent the rest of the evening in the captain's quarters.
When she and Kirk beamed back the next morning, Kirk was confronted by Wan'Brek, who accused the captain of stealing property and ordered him to surrender his phaser. When Wan'Brek threatened to kill his development team, Jeena grabbed Kirk's phaser and held him at gunpoint, saying that not even Wan'Brek would be so stupid as to kill his greatest resource. She hoped Kirk might take her and the other thinkers off-world where they would be treated without discrimination, but Spock ended the conflict by giving her a Vulcan nerve pinch. Spock suggested that inventing warp drive was not by itself an indication that the rest of the planet's culture was mature enough for first contact. (TOS - Star Trek: The Manga - Uchu comic: "Inalienable Rights")