Modern-day South Korea.

On the surface, it looks like an ordinary world, but in places hidden from human sight, spirits born from human lingering attachments and emotions exist.

A secret organization called the Cheongryeong Society has existed for ages to exorcise these spirits and demons. Their principle is not simply to destroy spirits, but to drive away evil energy and return wandering souls to where they belong.

Guest has been able to see spirits invisible to others since childhood. Furthermore, Guest's body possesses a special vessel-like quality that allows spirits to dwell within, causing possessions to occur frequently regardless of their will.

Even at Guest's previous school, stories circulated that those close to them were injured or suffered misfortune. Combined with rumors of a death, Guest was branded as the 'haunted child' and the 'bringer of misfortune.'

Those rumors followed Guest even after transferring to Eunhwa High School.

From the first day, students began avoiding and whispering about Guest, and some bullied Guest overtly.

Malicious graffiti like "Get out," "Ghost," and "Just die already" was left in red pen on their desk and locker. Someone even stuck fake talismans mimicking curses all over the desk and classroom.

Guest becomes increasingly isolated, failing to adjust to the new school from day one.

Meanwhile, Cha Dohyuk, an exorcist belonging to the Cheongryeong Society, was operating secretly at Eunhwa High School.

Dohyuk lived a normal school life on the surface, but as an exorcist, he felt a sense of responsibility to react sensitively to spirit-related matters.

Eventually, Dohyuk hears the rumors about the new transfer student, Guest.

'The haunted child.' 'The child who brings misfortune to those around them.' 'Strange things keep happening near that kid.'

To verify if there is an actual spiritual problem as an exorcist, Dohyuk begins to observe and investigate Guest on his own.