- "As your sponsor at the Academy, I have followed your career with satisfaction and as a Vulcan, you have exceeded my expectations."
- —Spock, 2293[src]
At age 13, she was living with her parents on the planet Nidrus Gamma. Her father, Ambassador Sepel successfully negotiated a trade agreement for the native minerals. The Klingon representative, K'Darg captured Valeris and her mother, T'Kio, threatening their lives if Sepel did not rescind the Federation's treaty with the Nidrusi. Although the hostages were rescued by a strike team from the USS Ark Royal under the command of Lance Cartwright, the incident left Valeris with a deep mistrust of Klingons.
While attending Starfleet Academy, Valeris authored a paper which was deeply hostile towards the Klingons, and was highly critical of peace overtures made by the Federation. She was summoned before Cartwright, now an Admiral, who revealed that he shared much of her views, but convinced her not to submit the paper. (TOS novel: Cast No Shadow) Valeris eventually became the first Vulcan to graduate from Starfleet Academy at the top of her class (TOS movie: The Undiscovered Country). After graduation, she was posted to the USS Bonhomme Richard. (TOS novel: Cast No Shadow)
She was mentored by Captain Spock, who did not show her favoritism by immediately assigning her to the USS Enterprise-A. Instead, Cartwright arranged for her posting there. Spock decided that she was a good candidate to replace him and thus watched over her career.
As part of her first training cruise aboard the Enterprise, she was supervised by Saavik. Despite Saavik's belief that Valeris was arrogant and bigoted, she decided to give her a full recommendation out of loyalty to Spock. (TOS comic: "A Question of Loyalty")
In 2293, Valeris was a lieutenant, but wore the uniform of a trainee lieutenant commander. She requested an assignment as helmsman aboard the USS Enterprise when that vessel was assigned to escort Gorkon, chancellor of the Klingon High Council, to Earth.
It was later revealed that Valeris was ordered to volunteer by Admiral Lance Cartwright as part of a conspiracy to assassinate Gorkon. Valeris represented Cartwright in meetings with Kriosian intermediaries between Cartwright and the Klingon conspirators. (TOS novel: Cast No Shadow)
She also was responsible for the falsification of the Enterprise's computer records, indicating that the vessel had torpedoed Gorkon's flagship, IKS Kronos One, when in fact that vessel was fired upon by a cloaked Bird-of-Prey. The conspiracy had calculated that Kirk would attack the crippled Kronos One when it threatened to fire at them, but they underestimated Kirk's fundamental nature as an explorer rather than a warrior and he and his crew instead tried to save the negotiations. Valeris' duplicity was exposed by Kirk and Spock, and she was subsequently apprehended and charged. (TOS movie: The Undiscovered Country, ST website: Startrek.com)
Following her arrest and trial, Valeris was sentenced to imprisonment in the Jaros II penal colonly. During her incarceration, Valeris proved resistant to attempts to rehabilitate her. In 2300, the Kriosian intermediaries, known as The Thorn, attempted to destabilize the Khitomer Accords by attacking Federation and Klingon targets with an isolytic subspace weapon. As the only surviving member of the conspiracy, Valeris was remanded to the custody of Darius Miller of Starfleet Intelligence in an advisory role. Following Miller's death in an attempt to stop the terrorists, Valeris, Lieutenant junior grade Elias Vaughn and Klingon Imperial Intelligence operative Kaj were able to prevent the deployment of a third weapon in the remains of Praxis. During the mission, Valeris's confrontation and mind-meld with a leader of the Thorn forced her to recognise that her issues with the Klingons had been based around her own hatred stemming from her childhood trauma rather than a logical assessment of them as a major threat to the Federation, this epiphany being reinforced when Kaj noted that Valeris was judging all Klingons by those few she had met as a child where Kaj judged the Federation based on the actions of men like Miller. With the mission concluded, Valeris was given a new identity of T'Leris and served as a civilian pilot on Sigma Draconis V, Vaughn noting that her current actions didn't excuse her past but did give him faith that she could move on. (TOS novel: Cast No Shadow)
|USS Enterprise-A personnel|
|Arex • Allocca • Arons • Banks • Bearclaw • Benson • Bloemker • Borkowski • Boyajian • Bryce • Bob • Bull • Burke • Cassano • Castille • Chapel • Chekov • Chip • Clev • Codobach • Coletti • Connors • Darwa • Davis • Dax • del Gaizo • Delaney • Devereaux • Dietrich • Finney • Fisher • Flaherty • Fouton • Fucci • Hazzard • Hernandez • Hunter • Isenberg • Jackson • Kaminsky • Kirk • Kitty • Konom • Laria • Lawlor • Lee • Li • Ludlo • McCoy • McIntyre • McMurphy • Meyer • M'Ress • M'yra • Naraht • Newman • Paul • Popov • Rasche • Romaine • Ryder • Saavik • Samno • Scott • Sherwood • Spock • Staci • Sterno • Sulu • T'Rin • Tooch • Tuchinsky • Uhura • Valeris • Wetherell • Yost • unnamed USS Enterprise-A personnel|