11 timestamped notes explaining the Korean cultural context in this episode — customs, idioms, food, honorifics, and history, at the moment each appears on screen. These notes discuss events across the whole episode. To see them revealed scene-by-scene as you watch, use the episode page to find an airing.
The drunk tank Hwapyeong shares with the gangster is a 유치장 (yuchijang), a short-term police holding cell where people arrested for minor offences sleep off the night before formal processing. It is notoriously loud, cramped, and socially mixed — a white-collar drunk might end up next to a seasoned gangster, which is exactly the comic setup here.
The team leader explains that the station in Gyeyanjin wants to close a 20-year-old high-school girl's murder by pinning it on Kim No-seok, the recently deceased suspect. In Korea it is common for prosecutors and police to tie unsolved regional cases to a convenient deceased suspect to officially clear the file — a practice critics call '면죄부 수사' (rubber-stamp investigation). Kil-young's resistance to this is what drives her subplot.
Father Yang pours 소주 (soju), Korea's ubiquitous distilled spirit, as Yoon Hwa-pyeong opens up about a personal favour. Sharing soju at a low pojangmacha-style dinner table is a common Korean ritual for serious or emotionally heavy conversations — the act of pouring for someone signals that you are ready to listen without judgment.
Hwapyeong's grandfather dismisses the grandmother by saying this is a 세습무 (seseupmu) household — a family of hereditary shamans who inherit their spiritual role by bloodline, as opposed to 강신무 (gangsinmu), who receive a calling through sudden spirit possession. Because their gift is inherited rather than bestowed, they are traditionally seen as having limited power over spirits that arrive uninvited from outside the family line.
Seo-yun's great-grandmother was a 만신 (mansin) — the honorific term for a female shaman — from 평안도 (Pyongando), the northwestern region of the Korean peninsula now inside North Korea. Shamanism from that region has its own distinct ritual style, and descent from a Pyongando mansin is considered a strong sign that the gift will resurface in later generations.
The shaman 육광 says Seo-yun is fated to receive a 내림굿 (naerим-gut), a ritual performed when a spirit chooses a new host who is destined to become a shaman. Refusing the calling is believed to bring illness and misfortune to the person and their family — which explains why Seo-yun's grandmother is so frightened rather than simply taking her granddaughter to a doctor.
Yoon uses the word 빙의 (bingui), literally 'spirit riding,' to describe full demonic possession. He distinguishes it from what Seo-yun is currently experiencing — a preliminary stage where spirits circle her and make contact but have not yet taken over her body. In Korean folk belief and in this drama's internal logic, 빙의 happens in escalating stages, which is why the characters debate urgency: once full 빙의 sets in, expulsion is far harder.
The senior priest insists on 교구 승인 (gyogu seungIn) — formal approval from the Catholic diocese — before performing an exorcism. This reflects actual Catholic Canon Law (Canon 1172), which requires a bishop's explicit written permission before a priest may carry out a solemn exorcism. Yoon's history of performing unauthorised exorcisms is why he was stripped of the rite, and the same rule now blocks him from getting quick help for Seo-yun.
Yoon tells the senior priest that the demon they face drives its hosts to kill others, self-mutilate, and ultimately die by suicide. This is the drama's established signature for Park Il-do's possessions — each victim follows the same grim arc — and it is why Yoon argues that waiting for diocesan paperwork is a death sentence for Seo-yun.
Kil-young identifies the victim as a woman killed in a 뺑소니 (ppaengso-ni) — a hit-and-run — in Yeongwol, with the driver never caught. Hit-and-run is treated especially harshly in Korean law and culture; fleeing the scene of an accident you caused carries heavy criminal and social stigma. The drama suggests that the guilt and paranoia from covering up such a crime created the psychological 'gap' that Park Il-do exploited to possess Jeong Hyeon-su.
Hwapyeong realises that because Seo-yun is a natural 영매 (yeongmae), a person who can see and communicate with spirits, she is not just at risk — she is Park Il-do's ideal next host. In Korean shamanic tradition, a medium's open channel to the spirit world is a gift, but it also makes their boundary between worlds thinner than an ordinary person's, leaving them more vulnerable to a hostile entity forcing its way in.