Lee Yool loses his memory after falling off a cliff during an attempted assassination, wandering for 100 days under a new name and personality. That premise anchors 100 Days My Prince, a 2018 TV series from creators So Jae-hyun and Lee Jong-jae that mixes comedy, drama and mystery across 16 episodes on tvN.
Doh Kyung-soo plays Lee Yool/Won-deuk, while Nam Ji-hyun plays Hong Sim/Yoon Yi-seo, the head of the first detective agency in Joseon. Cho Seong-ha plays Kim Cha-eon, Cho Han-chul plays King, and Oh Yeon-ah plays Queen Park. The series aired from September 10 to October 30, 2018, every Monday and Tuesday at 21:30 KST.
Trailer, via Viu Philippines.
Lee Yool’s Fall
The setup is simple but effective. Lee Yool is the king’s nephew who spends his days playing instead of studying, with his best friend and guardian, Dong-joo. When he punishes peasant children during playtime, a girl named Yoon Yi-seo steps in to scold him. She is kind, smart and compassionate, and Lee Yool develops a crush on her, changing to become more studious to impress her.
The Family Plot
Lee Yool’s father is ambitious and jealous of his brother, the King, vying for the throne. He schemes with Kim Cha-eon, who promises reward for overthrowing the King. One night, Kim Cha-eon murders the King and his men, including Yi-seo’s father, the general and right-hand man. Yi-seo’s father tells his elder son Seok-ha to take Yi-seo and run before Cha-eon wipes out the family.
The Twist
Cha-eon is about to strike Yi-seo’s father when Lee Yool emerges from hiding, threatening to report him to his father. Instead, Cha-eon takes Yool to his father’s mansion, revealing the two have been conspiring together all along. This twist removes Yool from the scene as the coup succeeds.
Hong Sim’s Agency
Hong Sim runs the first detective agency in Joseon. Her role is central to the mystery framing, though the source does not describe her methods in detail.
Supporting Cast
Cho Han-chul plays King, Oh Yeon-ah plays Queen Park, Ji Min-hyuk plays Prince Seo-won, Kim Seon-ho plays Jung Je-yoon, Jung Hae-kyun plays Hong Sim’s stepfather, Han So-hee plays Kim So-hye, Heo Jung-min plays Kim Soo-ji, Kim Jae-young plays Moo-yeon, and Jo Hyun-sik plays Eunuch Yang.
Cable Ratings
100 Days My Prince is one of the highest-rated Korean dramas in cable television history. Its success on tvN suggests the mix of royal intrigue, romance and comedy hit its audience’s sweet spot.
Verdict
The series balances tragedy with lightness, with Lee Yool’s fall serving as both a plot device and a character arc. The twist involving Cha-eon and Yool’s father is sharp, and the chemistry between Lee Yool and Hong Sim grounds the fantasy in something viewers can care about.
| Element | Strength |
|---|---|
| Premise | Strong memory loss hook |
| Romance | Central to the story |
| Mystery | Underpins Hong Sim’s agency |
| Acting | Solid across the cast |
| Pace | Quick across 16 episodes |
100 Days My Prince earns a 7.9/10.
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