Sam, a high school senior and Patrick’s stepsister, also takes Charlie under her wing. At the beginning of the novel, Sam seems like she has everything: she is beautiful, she is spontaneous, and she has a group of friends who love her. Charlie immediately develops a crush on Sam that persists and only grows in strength throughout the novel, despite the fact that Sam dates Craig, a male model, for much of the middle portion of the novel. Part of the idealistic portrait of Sam throughout the novel stems from the fact that Charlie narrates every description of her, so she is naturally going to be portrayed in rose-colored glasses. Charlie is even diplomatic about Sam’s relationship with Craig, claiming that he is sad for Sam when the two of them break up.

Charlie uses his love for Sam as a sort of emotional lodestone throughout the novel. Until the very end of the book, Charlie never acts on his love for Sam. He has the opportunity to become touchy-feely with her during a performance of The Rocky Horror Picture Show, but Charlie wants his first time with Sam to be intimate, so he merely plays the role instead of participating fully in the part.

Sam, like Charlie and Patrick, also has personal demons. Sam was sexually abused as a child, which might help explain some of the deep bond that Charlie feels towards her, even if this bond is subconscious for almost the entire novel. Like Patrick, Sam gets betrayed by her romantic partner in the novel, when it is revealed that Craig has cheated on her multiple times. At the end of the novel, Sam and Charlie start to become sexually involved, and, for a brief moment, events seem to have lined up for Charlie in a moment of romantic glory. However, this glory is interrupted by Charlie’s repressed memory of abuse coming to the surface. Although Charlie might have preferred to continue his actions with Sam rather than face his demons, Sam unwittingly gives Charlie the greatest gift of all. By loving Sam so much, and by starting to act on that love, Charlie is finally able to unlock his most suppressed emotions, and in doing so, eventually mature into the kind of person who can both give and receive love.