In TVING's original series 'Monstrous,' Koo Kyo Hwan, Shin Hyun Been, Kim Ji Young, Kwak Dong Yeon, and Nam Da Reum experience hell in their hearts. Chaos, terror, madness, and determination all have different faces that seem to hint at their fate in the face of unexpected powers. The drama follows Jung Ji Hoon (Koo Kyo Hwan), an archaeologist who investigates weird supernatural phenomena, but his life is turned upside down by an unexpected case.

He now manages the YouTube channel Monthly Strange Story and produces the esoteric journal Monthly Strange Story. He travels to Jinyang County to explore 'Gwibul' because of his ex-wife, Lee Soo Jin (Shin Hyun Been) (a Buddhist statue possessed by an evil spirit). There, he encounters a strange and terrifying occurrence.

As an archaeologist, Lee Soo Jin deciphered writings and symbols. She was a natural at what she did. Her lone kid, however, dies, and she relocates to Jinyang County. Lee Soo Jin encounters strange occurrences there, prompting her to seek explanations.

The presence of Kim Ji Young, who portrays the tough cop 'Han Seok Hee,' is also noteworthy. Han Seok Hee fights to save her son Han Do Kyung (Nam Da Reum) from an unknown incident that occurred in her town, combining her distinctive appeal with her leadership. Her infatuation is complete, as evidenced by her shocked expression and the remark "I will absolutely save you." With just one insane look, Kwak Dong Yeon, who has entirely inhabited troublemaker 'Kwak Yong Hoo,' generates goosebumps. The catastrophic calamity that devastated the community is mainly of interest to Kwak Yong Joo, who appears to be a fairly unscrupulous figure at first appearance.

Nam Da Reum captures Han Do Kyung's rage, as he is the only one in Jinyang Gun who retains his good will despite the pandemonium. He wants to live a normal life free of commotion, but a calamity strikes one day, reawakening Han Do Kyung's resistance.