Lucy is the fourth child to Homer and Marge, and non-identical twin to Maggie. Shortly after she was born, Lucy was kidnappned by Hired Goons of a time travelling Dark Maggie to train Lucy as a warrior against Maggie herself. Marge tried to stop them but couldn't keep up, so instead she sought help from a bystander in the hospital who turned out to be a sixteen year old Maggie, trying to learn what happened to Lucy.

Over the next nine years, Lucy was injected with Mako Energy to help her fight, and trained with an Onion Sword, along with her best friend Abby Lamaze. The two were occationally sent on missions throughout Gaia. Both were at the mercy of Dark Maggie and Mr. Burns because of a Slave Crown they both wore.

Eventually in 5008, Lucy would be summoned to Hollow Bastion by Dark Maggie to fight none other than her own family, though she didn't know that. Bart, Lisa and Maggie fought her with the help of Squall Leonhart.

Once rescued by Lisa and Maggie in 2008 from the Nuclear Plant, Lucy aids Bart, Lisa and Maggie in tracking down Exdeath and Dark Maggie as revenge for being kidnapped and denied a proper childhood. She travels to Planet R, and finally defeats Dark Maggie.

Afterwards, Lucy is sent to school, but because of fears of her kidnapping are still high, the family agree to send her to Balamb Garden under the mentorship of Squall, while at the same time, learning Springfield lessons through a video feed Professor Frink invented. By the age of 15 Lucy manages to gain a SeeD qualification from Balamb Garden, but decides to stay in Springfield and study at Springfield High.

At 17, Lucy is in her senior year at high school, where after visiting friends Locke Cole and Terra Branford in Gaia, with Bart, Lisa and Maggie she returns home to find nothing but ruination, once again due to Dark Maggie messing with the Time-Space Continuum. She leads her family into battle and defeats Dark Maggie as well as the Dark counterparts of Bart, Lisa and herself as well.