Seventh grader Mallory Moss, who goes by the name “Mal,” is a student at Gibbons Academy middle school in Norwell, Florida. During the school’s annual Christmas concert, Mal and her best friends, Reagan and Tess, receive news that a classmate named Jennifer Chan has run away from home and is missing. Mal begins to fret and struggles to take her mind off an event from the previous Friday she calls “the Incident.” Tess, an overactive gossip, worries that Jennifer may have spoken to the authorities and is trying to get them in trouble. Mal reasons that what they did last Friday wasn’t that bad or even illegal. As the audience’s phones begin to ping and buzz, Mal refers to her town as “Nowhereville,” a dull place where news spread fast.

Reagan reassures Mal that everything will be fine, but Mal feels anxious and desperate. Being with Reagan is the only thing that makes her feel secure, and she is disappointed when their sleepover is canceled. Mal’s thoughts flash back to the Incident in the chapel’s basement bathroom. She hears Reagan’s voice taunt Jennifer.