For centuries, a legendary group known as the Hunters has stood as Earth's protectors against demons. These formidable women harness the power of their voices to create the Honmoon, a protective shield that prevents evil entities from reaching the human realm. The leader of this new iteration of Hunters, Celine, oversees a KPop group called Huntrix, composed of three talented young women: Rumi (Arden Cho), the lead vocalist with a hidden heritage; Mira (May Hong), the "black sheep" of her family; and Zoey (Ji-young Yoo), the group’s sweet yet fierce rapper. Together, they not only aspire to entertain but also aim to channel their musical talents into creating a Golden Honmoon that will permanently shield humanity from the demon king Gwi-Ma (Lee Byung-hun) and his minions.
The narrative unfurls in the present day when Huntrix prepares for a live performance while on their private jet. Their manager, Bobby, urgently contacts them, as their fans eagerly await their arrival. But chaos ensues when they discover that the flight attendants are, in fact, demons. Huntrix springs into action, performing their hit song, "How It’s Done," while battling the airborne foes. Their escapade concludes with a spectacular entrance onto the stage, thrilling an audience of adoring fans, even as they dispatch the last of the demons.
Meanwhile, Gwi-Ma becomes furious with his demon followers, punishing them for their failure to capture human souls. Strategic insights from Jinu (Ahn Hyo-seop), one of Gwi-Ma’s oldest demons, lead to the formation of a boy band known as the Saja Boys. Their mission: to undermine Huntrix by enchanting their fans and strategically dismantling the Honmoon. As Jinu conceals his own tumultuous past, he sets out with comrades Romance, Mystery, Abs, and Baby as they seek to undermine Huntrix's growing influence.
As the hiatus looms for Huntrix, Rumi unintentionally reveals her half-demon lineage while struggling with her singing voice. In a quest to restore her vocal prowess, the trio seeks guidance from Healer Han (Daniel Dae Kim), who prescribes remedies while casting an insightful gaze into their spirits. Their lives take a complicated turn when they cross paths with the Saja Boys, leading to a tumultuous rivalry filled with entertaining antics as the groups clash both musically and physically.
In the fallout of their encounter, the stage is set for a showdown at the upcoming Idol Awards. Amidst the backdrop of rivalry and self-discovery, Rumi grapples with her identity as the bond between her and Jinu deepens. Revelations about their histories reveal profound connections, intertwining tales of sacrifice and regret. As tensions culminate, Mira and Zoey must confront their feelings of betrayal when Rumi’s secret is brought to light, stirring emotions and challenging their sisterly bond.
Rumi resolves to embrace her demon side, steering the group to confront the Saja Boys at the Namsan Tower, where a grand performance is slated to ensue. The Saja Boys’ plan to harvest souls reaches its peak, causing a confrontation echoed in powerful choreography and heartfelt lyrics. When Gwi-Ma retaliates, Jinu steps in, sacrificing himself for Rumi, thus amplifying her abilities and love for her newfound friends.
The film climaxes with a triumphant triumph over Gwi-Ma and the dismantling of the Saja Boys, ultimately restoring the Honmoon and reaffirming the strength of friendship and acceptance among the trio. In the end, Rumi, Mira, and Zoey come together once more, ready to embrace their fans and continue their journey, even as Jinu’s loyal companions watch over them from the shadows.
