The Perks of Being a Wallflower is a novel written from the point of view of a high school freshman, Charlie. The novel is structured as a series of letters that Charlie writes to an unnamed friend, and these documents chronicle Charlie's trials, tribulations, and triumphs as he goes through his first year of high school. He begins writing soon after the suicide of his friend Michael, and he feels very alone in the world as school starts. Early in the year, Charlie meets an older student named Patrick, and Patrick introduces Charlie to his step-sister, Sam. Charlie later meets the rest of Sam and Patrick's group of misfit friends, and the resulting sense of community enables Charlie to feel more comfortable in school. Even though he is a wallflower who mostly sits back and watches the lives around him, Charlie tries hard to participate and to be more in control of his world. Assisting Charlie on his emotional journey is his English teacher, Bill, who pays special attention to Charlie and assigns him extra books to read and papers to write for personal enrichment.
Although Charlie chronicles his adventures with his new friends in the letters, his writing also reflects the larger personal problems that he deals with everyday. Charlie constantly worries about other people and tries to determine what is going on beneath the surface of society. As the story continues, Charlie's mental instability becomes clearer. He is obsessed with his Aunt Helen, who died on Charlie's birthday when Charlie was a young child. Charlie feels persistent guilt about this death because Helen died while buying Charlie a second birthday present. His love for Aunt Helen is unwavering.
At different points in the story, Charlie meets people who deal with difficult personal issues: cheating, abortion, and drug use. Many of these individuals have been sexually abused, but Charlie does not react strongly to such information. It is not until the end of the novel, when Charlie is about to have sex with Sam, that Charlie realizes that Aunt Helen had sexually abused him. He begins to have a breakdown, but his friends are there to lend assistance. When Sam leaves for college soon after this revelation, Charlie's downward spiral continues. His parents find him naked and disoriented, and he is hospitalized in due course. After undergoing several weeks of therapy, he comes to terms with the fact that his Aunt Helen had molested him every week when he was a young boy. His immense love for her led him to suppress the memories these events.
Charlie closes the novel by announcing that he may no longer need to write his letters. He has started to believe that he has agency over his own life and that he does not need to be defined by his past. Charlie's development and growth as a character demonstrate the perks, and the drawbacks, of being a wallflower.