Lee Woo-bin waits for Koo Bon-ha to perform at Club Debai, a small rock venue where the two live and make music. Bon-ha begins a song but abruptly walks away, leaving Woo-bin to finish it. Their argument continues through a series of rock numbers.

Bon-ha suffers from severe headaches and asks for his medication, but Woo-bin refuses because the pills nearly killed him before. As Bon-ha continues singing, he slips into a dreamlike state and remembers a woman he believes he loved. Woo-bin encourages him to leave the club and become famous, but Bon-ha is afraid because he has no official identity documents.

“Koo Bon-ha” is not his real name. It belonged to the club’s former owner, who sheltered a homeless boy dreaming of becoming a rock musician and gave him his name.

When Bon-ha later encounters the mysterious woman and brings her to the club, he collapses. After awakening, he learns that she has been murdered and that he is the principal suspect. Unable to remember what happened, he asks Woo-bin for the truth. Woo-bin claims that he was also there and killed her.

Club Debai disappears, and Bon-ha finds himself restrained inside a psychiatric institution. The woman is revealed to be his mother, who abandoned him 20 years earlier. She had returned not for him but in search of the original Koo Bon-ha, the man she once loved and whom Bon-ha now resembles.

Woo-bin finally reveals that he is another personality sharing Bon-ha’s body. Bon-ha has spent three years hospitalized under suspicion of his mother’s murder, while the prescribed medication threatens Woo-bin’s continued existence. Woo-bin coaches Bon-ha to testify that he did not commit the crime, enabling their release.

Back at Club Debai, Bon-ha approaches the microphone, but Woo-bin takes control of the performance. The precise final image may vary by cast, but the ending leaves Bon-ha increasingly bound to the identity that once helped him escape.