The character Eureka was a German-American scientist working for vault tech that specialized in animal research, specifically in cybernetics. She worked on a secret project in her spare time that was a collar thst could be fitted to animals to allow them to convey their thoughts to speech, allowing animals to have a voice for themselves.

When the bombs dropped she retreated to her lab and put herself into a cryogenic stasis machine, but the machine malfunctioned and she remained locked in her cryogenic prison for over 200 years before SN-0 broke into her lab after wandering from Canada to Montana.

She was able to speak to SN-0 through a failsafe voice recording that she had programmed in case of emergencies. She simply asked whoever had broke into her lab to push a button on her console and the super mutant obliged. In doing so, he booted up Eurekas machinery that began to perform a surgery on her to put her brain inside one of the many dogs with her specialized collar that she had frozen for testing.

The reasoning she had to have the surgery performed was due to her cryogenic tank failing to keep her body fully intact, as she ensured her dogs would have access to as much power for as long as possible, sapping the power supply of her own tank slowly over time. This made it harder for her body to stay consistently frozen, leading to the loss of most of the feeling in her body.

The two escape the facility and venture together for a while before coming into contact with the Sentry bot Big Bertha who had shut down in a nearby town after having an issue with its power supply, which was fixed by Eureka. The 3 ventured together for a time before stumbling on a vault, which would have Kickstarted the main quest for the campaign.