Tincoo was a Qomar mathematician, who was working aboard a Qomar transport in 2376. On their way back to the Qomar homeworld, the shuttle's propulsion system was damaged by the scanning beam of the USS Voyager.
Voyager brought them aboard, repaired their shuttle, and healed their injured. While in sickbay, unhappy about working with the primitive holographic Doctor, she and her associates heard the Doctor hum a song.
They were fascinated by it, as their race had never heard anything like music. She served as the intermediary between the planet's Prelate Koru and Voyager, as he requested a concert aboard Voyager. Afterward, when the Doctor became a celebrity on the planet, she served as the Qomar representative to the Doctor. He even inspired her to create a musical composition of her own, which he wasn't able to perform. She asked him to stay on the planet, and he believed she had developed a romantic interest in him. However, he realized she hadn't, when she developed a new, better singing hologram. The Doctor had a final performance, and then Tincoo revealed her new holographic construct. (VOY: "Virtuoso")