12 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.
영훈 says the incense stick is a '선악과' (seon-ak-gwa) — literally the fruit of the knowledge of good and evil from Genesis, the one God forbade Adam and Eve to eat. In Korean Christian tradition the term is shorthand for something irresistibly tempting but cursed. He is warning 선우 that using the magical incense feels like gaining divine power while carrying a price that will destroy him.
The Gyeongchun Line connecting Seoul's Cheongnyangni Station to 춘천 (Chuncheon) was a beloved escape route for young Seoulites from the 1970s through the 2000s. Catching the first train at dawn — before parents woke up — was a classic teenage adventure, romanticised in countless songs and dramas. 춘천 itself is famous for 닭갈비 (spicy stir-fried chicken) and a lakeside atmosphere that made it the go-to day-trip for young couples.
Before smartphones, exchanging handwritten 크리스마스카드 (Christmas cards) was a major school tradition in South Korea throughout the 1980s and 90s. Students gave them to classmates and crushes, and your handwriting was recognisable to anyone who knew you well — which is exactly why 영훈 can't deny writing it. The card here is the drama's clue that teenage 영훈 had feelings he wasn't ready to admit.
기일 (gi-il) is the yearly anniversary of a person's death, and visiting a grave or memorial on that exact date is a serious family obligation in Korea. Missing your own father's 기일 for twenty years — as 정우 apparently has — would be seen as a deep failure of filial piety (효도, hyodo). 유진 points this out gently but pointedly, signalling how fractured the Park family has been.
A prospective father-in-law visiting a young woman's workplace to personally order her to break up with his son was not unusual in conservative Korean families of the 1980s–90s. Parents held enormous authority over marriage choices, particularly when class, education, or family background were seen as mismatched. 유진 recalling that 천수 came to her shop without raising his voice — yet made her feel she had no choice — captures exactly that quietly coercive power dynamic.
Propofol — called '우유 주사' (milk injection) by Koreans because of its white colour — became a high-profile abuse issue in South Korea in the 2000s–2010s, particularly among medical professionals who could access it easily. Several celebrity cases made national headlines. 유진 describes 정우 getting it through the hospital, which fits the documented pattern; it is used medically as an anaesthetic but causes euphoria and dependence.
The press conference scene echoes real South Korean bioethics controversies, most notably the 황우석 (Hwang Woo-suk) stem-cell scandal of 2005–2006, in which eggs were harvested from junior researchers and low-income women under coercive or deceptive conditions. That case shook public trust in medical research. Viewers watching 최진철 deny everything on live TV would immediately recognise the template.
철민 winding down a tense conversation by suggesting they share a glass of 소주 after the evening news is a quintessentially Korean workplace ritual. 소주 (soju, a clear distilled spirit) is the default drink for colleagues processing stress or bad news together. The casual phrase '한잔 꺾자' — literally 'let's crack open one glass' — signals that despite the harsh words, the bond between them is intact.
선우 immediately tells 진철 he is recording the call — a deliberate journalistic tactic. Under Korean law, one-party consent recording (where one person in the call records it) is generally permissible, and recorded threats or admissions carry real evidentiary weight. Journalists in Korea routinely 녹취 (record) sensitive calls precisely because of this. 진철 saying he doesn't care is either bravado or a sign of how rattled he already is.
The flashback reveals that 진철 was building a '비자금' (bi-ja-geum) — an off-the-books slush fund — to finance a bio-research centre without 천수's consent. In Korean corporate and hospital culture, a 비자금 is a serious crime; its exposure typically means criminal charges for embezzlement or breach of trust. The tension in the scene comes from 천수 holding all the institutional power (원장, hospital director) while 진철 holds the money — and a dangerous outside backer.
선우 realises each time he lights the magical incense stick (향) and travels back in time, his body's remaining lifespan in the present shortens. This is the show's central supernatural rule, and he is only now feeling it physically. The word 향 (hyang) normally refers to the incense burned during ancestral rites (제사) — its use here ties the time-travel device to deeply Korean ideas about the living maintaining a connection with the dead.
현재의 선우 has travelled back to directly instruct his teenage self, a moment Korean dramas sometimes call '과거의 나' (my past self). What makes this culturally resonant is the speech level: 선우 uses informal speech (반말, banmal) to his younger self — natural between the same person — while the younger 선우 is terrified and speechless. The older man saying '반갑다' (nice to meet you, casual form) to himself is both eerie and darkly funny.