In 2374, she covertly boarded USS Voyager on the trail of Reskat. After she was discovered, she collaborated with the crew to apprehend her target, during which she fell in love with Commander Chakotay. As a result, she later returned to Voyager seeking asylum.
Her ship was critically damaged in a battle with another tracer, but she was beamed aboard Voyager. No one aboard Voyager remembered her, however, due to the pheromones produced by her species. Kellin presented evidence for her former visit, and over time Chakotay came to care for her once more.
Meanwhile, Voyager continued to be hunted by tracers intent on retrieving Kellin. Though she helped Voyager repel another attack, the tracer Curneth had slipped aboard undetected during the battle. By the time Kellin realized he was aboard, he was in position to erase her memories with a neurolytic emitter.
As her memories of Voyager faded, Kellin asked Chakotay to tell her afterwards of their time together, as she did for him before. However, when she regained consciousness in sickbay and Chakotay told her their story, she could not see herself as the person he described, who would violate one of their society's most important edicts. Thus, she elected to return to Ramura with Curneth. (VOY: "Unforgettable")