When she was younger, her mother remarried a man that Brenna only referred to as "The Hand." As a result of systematic abuse by the Hand, she became psychologically twisted. After her stepfather was killed by the Borg at the Battle of Wolf 359, she began to view the Borg as an image of stability and control and began to admire them for the power their collective mind gave them.
Believing Earth needed stability and control in the tenuous aftermath following the end of the Dominion War, Covington, conspiring with Trevor Blake and a modified version of the EMH Mark 1 whose ethical subroutines had been deleted, plotted to create a new Borg Collective out of Earth's population (using a nanite virus left on planet's following a Borg ships' destruction; which was found to have infested Earth secretly following the destruction of the Borg Sphere in orbit of Earth shortly before first contact, but remained dormant without the proper activation signal), with Covington as its queen. As such, Covington was altered surgically by the EMH. She worked out of a hidden lab adjoining her office and hidden by a holographic disguise.
Covington's plan was flawed, as the salvaged Borg technology was more inefficient and less effective than standard Borg equipment, and the virus, when activated, only triggered and began transforming those who were young, old or ill. With time, however, the plan was on the verge of succeeding, as the Earth's population was soon in danger of mass assimilation within days, Covington remained unsuspected, and all blame placed on the crew of the newly-returned USS Voyager, with its former-Borg crewmates Icheb and Seven of Nine being arrested and slowly tortured at Starfleet Headquarters.
Her plans were undone when Libby Webber, one of her most promising SI Agents, secretly supplied Vice Admiral Kathryn Janeway and her senior officers and other respective allies with information that pointed to Covington. Covington, however, realized this, and used the nanites to take control of the population of Starfleet Headquarters, preventing them from stopping her.
After a pitched battle with the Borg-Human Drones, the Starfleet team succeeded in reaching Covington, who by this time was totally immersed and connected to the building itself with Borg technology (unlike proper Borg Queens who have perfect mobility), and Seven deliberately went into the new collective hive mind created between Covington and the drones. In a telepathic battle of minds, Seven vanquished Covington, physically killing her. Covington briefly lived on, transferring her consciousness to Seven and making her the new queen. Covington's attempts to make Seven accept her place failed, and Seven shut the link down, freeing the drones, deactivating the nanite virus and erasing Covington from existence. (VOY novels: Homecoming, The Farther Shore)
- It is implied in the text of the Voyager relaunch novels in which she appears that she is the victim of systematic sexual and physical abuse at the hands of her stepfather.