While walking along the beach in his hometown, aspiring songwriter Jon Burroughs witnesses a man named Lucas trying to drown himself. As Lucas is taken to the hospital, Jon meets Don, who explains that Lucas was the keyboardist for a band called The Soronprfbs, which Don manages. After mentioning that he plays keyboards, Jon is invited to perform with them that night. The Soronprfbs' drummer Nana, synthesizer and theremin player Clara, and guitarist Baraque are reluctant to accept Jon, but he is warmly welcomed by lead vocalist Frank, who always wears a
papier-mâché mask over his head. Their performance abruptly ends when Clara storms offstage after being shocked by an electrical fault. Frank invites Jon to be part of a Soronprfbs project. He agrees and accompanies them to a remote cabin in
Ireland, believing it will only take a few days, only to realize they are set to stay there for a whole year. One day, Don confesses to Jon that he feels he cannot live up to Frank's prowess. The next day, Don reveals they are being evicted from the cabin, but Jon offers to pay the outstanding rent using his grandfather's inheritance. After completing their debut album, the band finds what appears to be Frank's corpse hanging from a tree, but upon removing the mask, they discover it is actually Don. After they cremate him, Clara reveals to Jon that Don was the band's original keyboardist. Jon reveals that he has been secretly uploading the band's recording sessions on social media, earning them a small fan following and an invitation to perform at
South by Southwest. Most of the band is offended by Jon's clandestine promotion of them, but Frank, excited by the prospect of a large audience, agrees to go to the festival. Clara confronts Jon as the latter is soaking in the hot tub, expressing contempt for his growing influence over Frank. The ensuing argument culminates in them having angry sex, and Clara threatens to stab him if the trip to America goes awry. The band begins to argue over creative differences leading up to the performance. Clara and Frank disappear shortly before the concert; Jon finds them in an alley, where Clara is helping Frank stave off a mental breakdown. Jon tries to get Frank to return to the festival with him, prompting Clara to stab him in the leg as promised. After she is arrested, Jon uses the scandal to build publicity for the band. The night before the concert, Nana and Baraque quit the band. Jon and Frank go onstage by themselves in spite of Frank's deteriorating mental health. When Jon tries to begin the set with one of his own songs rather than one from the album, Frank has a breakdown and collapses on stage. They move into a cheap motel together, where a frustrated Jon tries to forcibly unmask Frank. Frank tries to escape and is hit by a car, smashing the fake head. He flees before Jon can see his face. Sometime later, Jon visits a
dive bar where Clara, Nana, and Baraque are playing as a trio, and apologizes to them for having taken control of the band. After numerous failed attempts, he finally succeeds in tracking Frank to his hometown of
Bluff City, Kansas, where he is living with his parents. Jon sees Frank's real face for the first time, and discovers he is scarred and balding from prolonged use of the mask. Frank's parents explain that he has suffered from severe mental health issues most of his life, and began wearing the mask as a teenager after his dad made it for him for an alleged
costume party. When Jon suggests that Frank's suffering has led to his creativity and brilliance, his parents retort that Frank has always been musically talented, and that if anything, his mental illness has held him back. Frank declares he has been unable to make music since the band fell apart. Jon takes Frank to the dive bar where the others are playing; they quickly realize who he is and join him as he begins to sing. With the original Soronprfbs restored, Jon leaves the bar alone. ==Cast==