Frank Fisher, portrayed by Nick Offerman, is a former musician grappling with grief after the tragic loss of his wife in a biking accident. He runs a struggling vinyl shop, Red Hook Records, located in Brooklyn, New York. As the summer winds down, his daughter, Kiersey Clemons, who plays Sam Fisher, is preparing to leave for the West Coast to pursue pre-med studies. Despite her aspirations and her desire to spend quality time with her girlfriend, Rose, played by Sasha Lane, Frank persistently pushes her to engage in music with him.
During one of their jam sessions, Sam reveals that she has written a song titled “Hearts Beat Loud.” Excitedly, they spend an entire night recording and mixing the track together. However, in a moment of impulsiveness, Frank uploads the song to Spotify without Sam's consent, catapulting it into viral success.
Eager to form a music duo, Frank tries to convince Sam to join him, but she remains hesitant, focused on her medical career. Despite her rejections, Frank whimsically adopts the band name “We’re Not A Band”. Meanwhile, Sam secretly pens another song—"Blink (One Million Miles)"—which reflects her relationship with Rose, while Frank pours his heart into "Everything Must Go," a piece about his failing business.
Amidst this, Leslie, played by Toni Collette, who serves as both Frank’s landlady and a devoted customer, proposes a plan to rejuvenate Red Hook by converting it into a café. However, Frank resists her suggestions, refusing to adapt to the changing times.
The story takes a turn when a talent agent approaches Frank with an enticing offer for the band. Overjoyed, Frank shares the news, but Sam rejects the proposal outright. During an emotional confrontation where Frank mentions how her late mother might have supported the opportunity, Sam storms out, feeling betrayed and upset. Heartbroken, Frank declines Leslie's help to save Red Hook, leading to a botched last day of business marked by a major sale.
However, reconciliation occurs when Sam returns, and she persuades her father to perform live music together while customers browse the shop. They play their heartfelt songs—“Hearts Beat Loud,” "Blink (One Million Miles)," and "Everything Must Go," captivating the growing audience that includes Leslie and Rose.
As summer concludes, Red Hook Records ultimately closes its doors, and Frank fills the void by accepting a position at a bar owned by his longtime friend, Ted Danson, named Dave. In the final moments, Leslie visits the bar, sparking an engaging conversation over drinks, while the camera slowly fades away. Meanwhile, Sam embarks on her new journey on the West Coast, performing “Hearts Beat Loud” solo during an open mic event, marking the beginning of a new chapter in her life.
