At the time of the superflu outbreak, Dayna is twenty-five and living in Xenia, Ohio. She is beautiful, athletic, physically strong, staunchly feminist, and has experimented with lesbianism before settling more comfortably upon bisexuality.
After the plague Dayna leaves Xenia in the company of two men. Outside of Williamstown, Ohio Dayna's party is set upon by "Doc" and "Virge" — former members of an Army detachment, sent to Akron during the plague in order to suppress the media and shoot looters. In the aftermath of the plague, they have been joined by two other thugs and form a violent gang, maintaining a "zoo" of eight captive women whom they use as sex-slaves.
The gang kills Dayna's two male companions and make her the fourth addition to their "zoo"; a later captive is Susan Stern. The women are kept under control using pills dispensed at routine intervals by "Doc" (hence the nickname.) But when the gang spots Stu Redman's party near the Ohio-Indiana border and begins plotting to attack them, the "zoo" women hatch a counter-plot to fake taking their pills, so they will be alert enough to stage a revolt.
Doc's men intercept Stu's group, intending to kill the men and enslave the women. The "zoo" seizes this moment to launch its coup, wrestling their jailors for their firearms and distracting them long enough for Stu, Harold Lauder and Fran Goldsmith to open fire on them. Between their joint efforts, Doc and his gang end up massacred.
At this point Fran has not yet made her feelings for Stu known to him, and initially sees Dayna as a potential rival for his affections. She becomes especially nervous when the two show signs of warming up to one another (a fact silently, though smugly, noted by Harold.) This prompts Fran to stop vacillating and finally reach out to Stu, who reciprocates and they become an official couple.
Later on Susan Stern — citing Dayna's strength and fearlessness — recommends her to the Boulder Free Zone Committee as the second scout to go spy on Randall Flagg's activities in Las Vegas. Before leaving, Dayna confides in Susan that she can do the Zone an even better service: if she can get close enough to Flagg she will actually assassinate him, using a spring-loaded knife strapped hidden to her forearm. But she also promises that she will "stick to the script" unless a truly perfect opportunity arises to dispatch Flagg.
Dayna is quickly welcomed into the Las Vegas community and assigned a job on one of their street-maintenance crews. She becomes coworkers and friends with former exotic dancer Jenny Engstrom, and even lovers with Lloyd Henreid, Flagg's second-in-command. While on work detail, however, she spots Tom Cullen and deduces that he too is spying for the Boulder Free Zone.
After Bobby Terry botches the mission to capture the head of Judge Farris in Oregon, Flagg reveals Dayna's identity to his underlings as the second spy, and she is brought before him. Expecting interrogation and torture, Dayna is surprised to find Flagg in a warm and gregarious mood. Although wary, she is nearly disarmed by his charm when he offers to let her return to Boulder. However, he does insist that she reveal the identity of the third spy; for whether due to Tom's retardation or his post-hypnotic instructions, Flagg is unable to see into his mind.
Flagg's good humor begins to evaporate when Dayna refuses to divulge her suspicions that the third spy is Tom Cullen. She attempts to go through with her backup plan of assassinating him, but he mockingly transforms her spring-loaded knife into a harmless banana.
In fear and desperation, knowing that Flagg will probably torture the information out of her, Dayna breaks a window and fatally cuts her own throat to protect Tom's identity. She bleeds out so quickly she is dead before Flagg can seize and pull her back.
Flagg explodes into fury, venting his rage on Dayna's corpse for some time. Finally he orders Lloyd Henreid to take the body of his former lover east of town, douse it in gasoline and cremate it. Dispassionately Lloyd obeys, later explaining to a child that he was "burning trash".