There's nothing like a jealous girlfriend to spice up an already hot summer romance. Kristina first makes Lince's acquaintance when she observes Adam and her making out from a distance—and at first, her intentions are about as far from stealing Adam as they could possibly be. "Guinivere really had him," Kristina explains, using a King Arthur reference to cast Lince as Adam's queen. "So why should I want him? I didn't really want his perfect pout, reaching hungrily for my own timid lips" (She Went Inside.1-2).
Whether she means to or not, though, Kristina supplants Lince as Adam's main girl, which possibly has consequences she can't possibly foresee: Under the influence of drugs after she gets high with Kristina, Adam, and Kristina's dad at the bowling alley, Lince confronts Adam about the nature of his relationship with Kristina. In a crank-induced fit of anger, "She looked like an animal, crazy, mad, diseased" (He Told Me Why Anyway.4), and ends up either falling or jumping from the balcony.
While Adam attempts to tell her otherwise, Kristina feels responsible for the accident, and her guilt carries her even further into the dysfunctional world of drugs that she's already become a part of. Not only does she think she's guilty because she made Lince jealous, but she also was passed out on drugs just outside when the accident happened. "Plenty of blame to go around," she says after hearing the news. "Too much truth in that. And I never heard a thing, dead to the world" (My Brain Somersaulted.4-5).
As Lince recovers from her fall, she also serves to push Kristina further from Adam and toward drug connections in her own town. Lince and Adam end up rekindling their relationship, and near the end of the book, Kristina learns that Lince is going to have Adam's child. So really, she recovers and everything works out in the end—sort of. Still, Kristina's experience with Lince is her first introduction to the potentially lethal consequences of drug use.