At the time of the superflu outbreak Lucy is a twenty-five year old housewife. She lives with her husband Wes Swann, and their young daughter Marcy, in Enfield, New Hampshire. Wes and Lucy married soon after high school due to Lucy becoming pregnant. Her parents thought little of the match, and even less of Wes, but the birth of Marcy seemed to galvanize their relationship into a happy. well-adjusted marriage.
After the plague killed everyone else in town, including her husband and daughter, Lucy nearly goes mad with grief until fellow survivors Larry Underwood, Nadine Cross and Leo Rockway arrive on their way to the Stovington Plague center. She joins their party and quickly becomes lovers with Larry, although he is still obviously preoccupied with Nadine.
When their destination turns from Vermont to the west, the growing party of plague-survivors heads towards the Boulder Free Zone. Fifty miles east of their destination, while camped for the night, Lucy confronts Larry about his fixation upon Nadine. She has no delusions about the nature of their arrangement, and knows that Nadine is both more attractive and alluring than her, while she herself must seem tawdry, common and cheap by comparison. Larry does not deny any of this, but protests candidly that he "loves her as much as he can."
Lucy declares that she would support his relationship with Nadine, free of any grudges or ill-will, if only Nadine would reciprocate his feelings, since love is important, and probably the only thing that will get any of the survivors through the ordeal of post-plague living. She does, however, warn Larry not to let himself get hurt in a fruitless pursuit of Nadine.
Later on in Boulder, Nadine tries to seduce Larry in a desperate attempt to break Randall Flagg's hold over her. Once Nadine offers herself up freely, Lucy is fully prepared for Larry to abandon her. But Larry demonstrates a great leap in character-growth by rejecting Nadine's advances, choosing instead to remain loyal to Lucy.
After Larry's death in the destruction of Las Vegas, that spring Lucy gives birth to Larry's twin children.