Eva's narration takes the form of letters written after the massacre to her husband, Franklin Plaskett. In these letters she details her relationship with her husband well before and leading up to their son's conception, followed by the events of Kevin's life up to the school massacre, and her thoughts concerning their relationship.
When relating the story of the massacre, Eva finally reveals that Franklin and Celia are in fact dead—Kevin killed them both with his bow before using this weapon to attack nine classmates, a cafeteria worker and a teacher. Eva speculates that he did this because he overheard her and Franklin discussing a divorce; he believed Franklin would get custody of him, thus denying him final victory over his mother.
The novel ends on the second "anniversary" of the massacre, three days before Kevin will turn eighteen and be transferred to Sing Sing. Subdued and frightened, he makes a peace offering of sorts to Eva by giving her Celia's prosthetic eye to bury, and telling her that he's sorry. Eva asks Kevin for the first time why he committed the murders, and Kevin replies that he is no longer sure. They embrace, and Eva resolves that she finally loves her son.
Shriver focuses on the relative importance of innate characteristics and personal experiences in determining character and behaviour, and the book is particularly concerned with the possibility that Eva's incongruity toward motherhood may have influenced Kevin's development.
Shriver also identifies American optimism and "high-hopes-crushed" as one of the novel's primary themes, as represented by Franklin, the narrator’s husband, who serves as "the novel’s self-willed optimist about the possibility of a happy family.”
Rationalisation for Kevin's behavior is one of the central themes of the story: when asked the simple question "Why?" after the massacre, he responds that he is giving the public the excitement and scandal that they secretly crave.
Love is another...