Rumi

For a long time, demons attacked humans and devoured their souls to feed the Demon King Gwi-Ma. Three women rose as demon hunters, defeating the demons and creating a barrier called the Honmoon to seal them out of the human world. This legacy was passed down through generations who used their singing voices to maintain the Honmoon. The current generation of hunters is the K-pop girl group Huntrix, made up of Rumi, Mira, and Zoey, mentored by Celine, a former demon hunter who raised Rumi. After defeating demons and finishing their world tour, Huntrix prepares to release their new single, until Rumi begins to lose her voice. It is revealed that she is part demon. In the past, Celine tells her that defeating all demons will create the Golden Hoonmoon that will seal away the demons for good, and that it might remove her demon marks. Huntrix then encounters a new boy band, the Saja Boys. Though nearly deceived, they sense something is off. They confirm that the Saja Boys are demons but fail to stop them in a scuffle; Jinu discovers Rumi's heritage and keeps it from Mira and Zoey. He meets with Rumi privately, revealing that demons are controlled by shame and misery through voices Gwi-Ma whispers to them. Jinu recounts how, 400 years ago, Gwi-Ma gave him a beautiful voice that helped lift his impoverished family. Jinu became a palace performer but was eventually banished to the demon realm and is haunted by guilt over his family losing everything.

As the Idol Awards approach, Huntrix rushes to create a new song to expose the Saja Boys, but their popularity rises; fans begin shipping the groups together. Mira grows suspicious, especially as Rumi questions if their song is too hateful toward demons. Rumi, torn between worlds, sympathizes with the demons and suggests to Jinu that if the Saja Boys help them win the awards and reshape the Honmoon, they could be free.After a horde of demons kill everyone in a subway car, Mira insists they focus on saving people instead of rewriting the song. Developing feelings for one another, Rumi admits to Jinu that her shame over her origins damaged her voice, but talking with him has healed it. After singing together, Jinu no longer hears Gwi-Ma's voice and vows to sabotage the Saja Boys at the Idol Awards. Gwi-Ma confronts him, reminding Jinu of their deal and the truth he hides: Jinu abandoned his family the moment he gained fame. Gwi-Ma threatens to return the tormenting voices.At the Idol Awards, the Saja Boys are absent, leading Huntrix to perform "Golden", focusing on unity rather than demon hatred. However, impostor demons posing as Mira and Zoey trick Rumi into singing "Takedown", revealing her demon marks to everyone. She flees the stage and runs into the real Mira and Zoey, who feel betrayed when she admits to her heritage and conspiracy with Jinu. Rumi confronts Jinu, who cruelly says it was all a lie. Rumi remains in denial, until he finally snaps and admits he abandoned his family when fame came, confirming what Gwi-Ma had said.Gwi-Ma casts a trance over Mira, Zoey, and the public, drawing them to the Saja Boys' final performance designed to shatter the Honmoon and unleash Gwi-Ma. Celine offers to cover up the situation, but Rumi refuses, embracing her demon side. She lashes at Celine, asking why she never fully loved her, then leaves.