Young and shy Quentin (Nat Wolff) is in for the night of his life when Margo (Cara Delevingne), the most popular student in high school, recruits him to help her play mischievous pranks on the friends who betrayed her. The next day, however, the mysterious Margo is nowhere to be found. With help from a few buddies and some cryptic clues that she left behind, Quentin embarks on an obsessive mission to find the girl who stole his heart and made him feel truly alive.