
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.

Lee Yul begins a secret investigation after growing suspicious of his worsening health. Yeon Hong-sim returns to Hanyang in search of her brother.

Yul uncovers the mastermind's identity and Kim So-hye's secret before coming under attack in the forest. Hong-sim is punished for refusing to wed.

Yul loses all memory, but gains a new identity as Na Won-deuk. Hong-sim begrudgingly chooses to become a wife to avoid life as a concubine.

Jung Je-yun searches for a link between the royal physician's murder and Yul's disappearance. Hong-sim puts Won-deuk to work to repay his debt.

News of the crown prince's passing is made public. Hong-sim is delighted to learn of Won-deuk's ability to read and write.

Hong-sim's reunion with her brother doesn't go as expected. Eunuch Yang notices something off about the crown prince's dead body.

Witnessing Won-deuk's martial arts skills, Hong-sim gets curious about his real identity. News of the queen's talisman sparks protest and debate.

Won-deuk celebrates an unforgettable birthday. Mu-yeon completes his final task for Kim Cha-eon and prepares to leave with Hong-sim.
Je-yun reunites with Hong-sim as the new county governor. To recover his memory, Won-deuk visits Hanyang and enters palace walls.

With Hong-sim and Won-deuk's help, Je-yun concocts a plan to get in Park Seon-do's good graces. Rumors swirl about the crown prince being alive.
Created by: So Jae-hyun, Lee Jong-jae
Available on: tvN