Jennifer Harris, a lisping, chubby nine-year-old being raised by a distracted single mother, is an outcast at school and the target of cruel and incessant teasing. Life would be unbearable except for the companionship of her childhood friend Cameron Quick, who is ostracized himself because of poverty and his quirky personality. Jennifer and Cameron are soul mates, drawing strength from each other to endure the painful struggles of growing up as social pariahs. Cameron, however, has difficulties at home far greater than any he must face at school. His father is an abusive reprobate, and one day, the entire family inexplicably vanishes.

Jennifer is devastated by Cameron’s disappearance, and eventually is led to believe that he is dead. When her mother remarries and Jennifer enrolls in a new school, she resolves to go on with her life and remake her image, losing weight, taking on an outgoing persona, and renaming herself Jenna. Although she must constantly be vigilant to prevent the old Jennifer from showing through her façade, things appear to be going well. Jenna is pretty and popular, and even has a boyfriend, when Cameron, eight years after he dropped from sight, reenters her life. Cameron’s return forces Jenna to come to terms with who she really is and to examine the true nature of friendship.

Themes of love and friendship are handled by the author, Sara Zarr, in an especially unique and realistic manner in Sweethearts, which was published in 2008. The story, which is written in spare but lyrical prose, is an examination of that special kind of relationship that is so much more than friendship, but is not really romantic love, perhaps because it transcends even that. Jenna and Cameron are separated by circumstances, each mindful of the need to become, and to allow the other to become, the best person they can be, even if it means they cannot be together. Years pass as the childhood friends live their separate lives, and although Jenna feels that it must be love which binds them, she wonders if her connection with Cameron can really be called love, when they never see each other and rarely even talk. Still, there is something undeniably precious, strong, and pure between the two of them, indefinable, but eminently significant. Cameron’s place in Jenna’s heart "is tender, a bruise of longing, a pulse of unfinished business." In the end, Jenna concludes that the mark she and Cameron have left on each other "is the color and shape of love." Cameron, the one person in her life who knows her completely and affirms her despite all, is "as much a part of (Jenna) as (her) own soul," and their love continues on, personified in memories, elusive and evolving, forever.