Su Hee-joo (played by IU)
A modern historian transported to Joseon — sharp, resilient, and caught between knowledge and conscience
Su Hee-joo (성희주)
Played by: IU (이지은)
Modern Age: 28
Modern Role: PhD student in Korean history, Seoul University
Joseon Role: "Book Recorder" under Prince Lee An's protection
Character Overview
Su Hee-joo is an academic obsessed with the Joseon Dynasty — particularly the reign of King Yeongjo. Her encyclopedic knowledge of this era becomes her greatest asset (and most dangerous secret) after she is transported back in time.
She faces a constant ethical dilemma unique to historians: she knows what will happen, but does she have the right to change it?
Key Traits
| Trait | Manifestation |
|---|---|
| Resourceful | Uses modern logic to navigate ancient court etiquette |
| Curious | Near-obsessive attention to historical detail |
| Principled | Torn between "non-interference" and helping those she cares about |
| Resilient | Adapts quickly under pressure |
| Modern-minded | Challenges feudal gender norms with quiet persistence |
IU's Performance
IU brings Su Hee-joo to life through meticulous eye-acting — her expressions shift between controlled composure and barely-hidden panic in ways that feel entirely authentic.
Highlights:
- Episode 1: Panic masked by quick thinking in her first encounter with Lee An
- Episode 3: Improvising her way through a political interrogation
- Episode 4: Breaking down upon discovering the archive — IU's most powerful scene to date
Relationship with Prince Lee An
| Stage | Su Hee-joo's Feelings | Key Scene |
|---|---|---|
| First meeting (Ep.1) | Fear, wariness | Wall confrontation |
| Getting acquainted (Ep.2-3) | Curiosity, testing | Moonlit garden exchange |
| Alliance (Ep.4) | Budding trust | Secret study meeting |