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.
The bitter crown prince leaves the palace on an investigation, and a woman is faced with marriage being forced upon her. Fate brings the two together in the most unconventional of ways.
The crown prince takes unconventional measures to investigate the conspiracy, but the answers are closer than he thinks. Troubles keep finding Hong Shim as the deadline for her forced marriage nears.
The prince, now known to everyone as Won Deuk, comes onto the scene, but refuses to just play along with getting married.
The prince's amnesia and shelteredness make grand problems for Hong Shim as her patience is pushed to its limits.
The prince's debt still looms over Hong Shim's head, while Officer Jae Yoon's investigation hits a snag.
Won Deuk grows more attached to his wife, and Hong Shim encounters someone she didn't expect.
The prince's memory returns bit by bit, while the affection that the Won Deuk in him feels for Hong Shim steadily grows. The palace, on the other hand, is turned upside-down with the investigation.
With the mayor gone, Songju Village readies for change. The prince starts to settle in his new marriage.
The prince returns to Songju with a startling revelation, while Jae Yoon's installment as mayor doesn't go as well as everyone hopes.
Hong Shim starts to fall for Won Deuk more and more. The prince, however, comes to a conclusion on his lost memories.