Katherine is an English teacher and single mother to her teenage daughter, Dana. A shocked Dana shares the news that Nathan Dugan, a former student of Katherine's, has gone on a shooting spree and killed himself. Katherine's ex-husband Jack calls and asks Katherine if she ever noticed anything off about the boy. Curious herself, Katherine goes looking for the short story Nathan wrote in her class several years earlier. The story is about a hunting trip, and reveals a deep obsession with guns. Combined with her memory of Nathan's strangeness and complete lack of social skills, Katherine begins to think she should have known, after reading this, that something was wrong. Unable to move on from her regret, Katherine drives out to visit Nathan's mother, Marielle Dugan. She doesn't make the connection she'd hoped: Marielle is closed-off and uninterested in Katherine's guilt or observations. Katherine leaves, understanding that Marielle and herself share different realities. As she arrives back to her lonely home, she recalls that her semester teaching Nathan took place the same spring her marriage fell apart and her daughter started rebelling, and that back then she had just wanted to be finished with Nathan Dugan.