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.

Woo Jin takes care of his son Ji Ho alone after his wife Soo A passed away. Before she passed away, she promised she would be back on a rainy day one year later. One year later, Soo A appears again, but she does not remember anything.