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.
Crown Prince Lee Yool / Won-deuk
Lee Yool (young)
Hong-sim / Yoon Yi-seo
Lord Park Sun-do
Hong-sim / Yoon Yi-seo (young)