As Nattie sorts through the evidence (the lyrics, Sebastian's elusive text messages, and their brief romantic encounter last year), the song's popularity skyrockets, and everyone starts speculating about "Natalie's" identity. If that wasn't mortifying enough, Nattie runs into another problem: her confusing, flirtation-packed feelings for her good friend Zach. With her once-average life upended, Nattie is determined to figure out once and for all if her short-lived past with Sebastian was something love songs are made of--or just a one-hit wonder.