While her brother Brian became a scientist like their father, Sir James Braddock, Betsy Braddock chose another path. A mutant telepath, she used her family name to avoid Sentinel attack and joined the Psi Division of S.T.R.I.K.E., the British division of the international espionage agency S.H.I.E.L.D. She swiftly rose to the rank of Colonel.
When the telepathic, reality-warping mutant David Xavier escaped the medical facility on Scotland's remote Muir Island, killing several people in the process, Betsy and Agent Dai Thomas were assigned to recapture him. They placed Moira MacTaggert, David's mother and facility head, under house arrest until Charles Xavier, her estranged husband and David's father, arrived on the island with his students, the X-Men. The elder Xavier's psi powers swiftly located his son, and the group cornered David inside a Burger King in Aberdeen. David took possession of Wolverine’s form and cut a swath through the X-Men, until Storm hit him with a lightning bolt and Betsy stunned him with a psychic grenade. David fled, jumping out of Wolverine and into the driver of an oncoming truck; right after the vehicle crashed, he jumped in to Betsy's mind.
Hidden within Betsy, David lured his parents and the X-Men to Germany, claiming that her psychic powers had tracked him there; however, Charles confronted him after realizing "Betsy's" mannerisms were those of a teenage boy, not an adult woman. David dropped the charade, took his parents hostage and transformed Betsy's body to resemble his own. He defeated the X-Men, but as he tried to kill Charles, Betsy's personality kicked in, jamming his powers. She told Charles he had to kill her before David could regain control, or flee; Charles refused, but the X-Man Colossus crushed Betsy with a car, killing her body and apparently slaying both the minds within.
Betsy, however, escaped the reaper; her mind made contact with Kwannon, a young Asian woman. Kwannon was relieved to have a chance to finally move on after ten years in a coma, and let Betsy claim her body. Awakening, she called her father, who had only just buried her and was overjoyed to find his daughter alive, whatever her form. Returning to active S.T.R.I.K.E. duty, Betsy was redeployed to help assemble the European Defense Initiative. She later met Colossus at an Xavier Institute reception, and told him she did not blame him for killing her, and in fact had found dying a fascinating experience.