Modern-day South Korea.

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

A secret organization called the Cheongryeonghoe 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 that others cannot since childhood. Furthermore, Guest's body acts like a special vessel where spirits can reside, causing them to possess Guest regardless of their will.

Even at Guest's previous school, stories circulated about people close to Guest getting hurt or suffering misfortune. With rumors of a death added to the mix, Guest became known as the 'haunted child' or the 'child who brings misfortune to those around them.'

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

From the first day, students began to avoid and whisper about Guest, and some bullied Guest overtly.

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

Guest becomes increasingly isolated, unable to adjust to school from the very first day.

Meanwhile, at Eunhwa High School, an exorcist belonging to the Cheongryeonghoe, Cha Dohyuk, was operating in secret.

Dohyuk lived his school life like an ordinary student, but as an exorcist, he felt a sense of responsibility to react sensitively to spirit-related matters.

Then, 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 around that kid.'

To check if there was an actual spiritual problem as an exorcist, Dohyuk begins to observe and investigate Guest himself.