- HD 1080
- Runtime: 75m.
- Status: Ended
- 1
- Languages: ko
- Country: South Korea
- Director: Lee Jong-jae
- Stars: Doh Kyung-soo, Nam Ji-hyun, Cho Seong-ha, Jo Han-chul, Oh Yeon-ah
- keywords: amnesia, marriage of convenience, romance, historical, double identity, joseon dynasty, ancient korea
- Production_studio: AStory, Studio Dragon
- Slogan: I will marry you someday.
- Seasons: 1
- Episodes: 16
- First air date: 2018-09-10
- Last air date: 2018-10-30
- providers: Netflix, Amazon Prime Video, Rakuten Viki, Netflix basic with Ads, Amazon Prime Video with Ads
- The 100 Days My Prince is featured in the top rankings of 2018
- #24 in Top Comedy Series of 2018
- #46 in Top Drama Series of 2018
- #10 in Top Mystery Series of 2018
Lee Yool falls off a cliff and nearly dies in an attempted assassination. He loses his memory, and wanders for 100 days under a new name and personality. During this period, he meets Hong Sim, head of the first detective agency in Joseon.