The central twist of the narrative is that Kim Hyun-ji was never dead. Five years prior to the story, while in possession of Bong-pal’s mother’s sacred Buddhist ritual weapon, she was struck in a hit-and-run orchestrated by Joo Hye-sung. Her wandering ghost persona was actually an amnesiac astral projection resulting from her comatose state in a hospital.
The malevolent spirit possessing Professor Hye-sung is revealed to be the exact same demonic entity that targeted young Bong-pal. Monk Myung-chul expelled it from Bong-pal years ago, but the exorcism resulted in the death of Bong-pal's mother, cursed Bong-pal with spiritual sight, and forced the demon to find a new host in the abused child Hye-sung.
In the final showdown at the old temple, Bong-pal wields the sacred Buddhist prayer bead bracelet, infusing his strikes with spiritual energy to permanently obliterate the shadow demon. Hye-sung survives and is imprisoned to face legal justice for his mortal crimes. Hyun-ji fully regains her memories of her time with Bong-pal, passes the university entrance exam, and enrolls in his department, cementing their romantic relationship and continuing their paranormal exorcism work as partners in Sundae Soup.