Sebastian Prendergast (Butterfield) lives a dull, unexciting life with his grandmother Jospehine (Ellen Burstyn) in an old tourist location known as the House of Tomorrow. Isolated with hardly any friends to connect with, Sebastian's life changes when he connects with Jared Whitcomb (Alex Wolff), a musician who introduces him to punk rock. Together, they form a friendship and Sebastian joins Jared as a guitarist in their band. The film tackles the awkward, uncomfortable feelings of growing up, and the impact of formative experiences.