In early 2367, Frazier, was aboard the Roosevelt when the ship participated in the Battle of Wolf 359. Frazier was among at least four crewmembers of the Roosevelt assimilated by the Borg during the battle and transported back to the Delta Quadrant. (VOY: "Unity")
Assimilation and freedom
The Borg cube that Frazier was on was disabled by an electrokinetic storm in 2368 and its link to the hive mind was severed. Frazier and the others who survived retrieved their pre-assimilation personalities and settled on a nearby M-class planet. When the former drones from different species began to attack each other, Frazier, her friend Orum, and others founded the Cooperative. Orum produced a prosthetic arm for Riley to replace her Borg-prosthesis. Over the years she considered the members of the Cooperative as her new family. Frazier set up a Federation distress call to get outside help such as security upgrades, medical supplies and some weapons.(VOY: "Unity")
Contact with Voyager
Her signal was finally answered by Chakotay and Ensign Kaplan in 2373, who landed on the planet. Kaplan was killed and Chakotay so severely injured by a rival faction, that he was linked to Frazier and others in an attempt to heal his wounds.
Initially, Frazier hid her Borg past, explaining her presence in the Delta Quadrant as "Seven or eight years ago, I was working as a science officer on a vessel in the Bolian sector. We were attacked without warning by aliens. They overpowered us in minutes and those of us who survived were put in some kind of stasis. The next thing we knew, we were here on this planet. It didn't take too many hours of stargazing to realize we weren't in the Alpha Quadrant any longer." A short time later Chatokay discovered the truth behind Frazier's abduction.
After establishing contact with the USS Voyager, Frazier wished to get Voyager's assistance in re-activating the neuro-electric field generator on the disabled Borg cube in order to stop the fighting and reestablish order. Captain Janeway refused, fearing a new collective.
Despite her rejection, Frazier used the Cooperative's former link with Chakotay to force him to go to the disabled cube and re-activate the generator, which he did. When the link was established, Frazier and the New Cooperative was able to restore order and she ended the neural link with Chakotay. (VOY: "Unity")