ang Yongguk is a detective police specializing in criminal case such as larcenies, murders, ual harassments, and so on. He was in charge of an unsolved grand larceny case of a precious gem stolen almost fifteen years ago. He has just met the main eyewitness of the case who was a long-term patient in a mental hospital. She is Park Eunha, the daughter of a late detective police handling this case before Yongguk. Yongguk has done some investigation to the case for years and found a stagnant as he couldn't find the main evidence of the case, the jewel itself. As one of the perpetrators took a suicide when he was about to be arrested and the other one was still fugitive, hence the only way to find it was to ask for any clue to Eunha.

Will Yongguk find the lost jewel? Will he resolve this unfinished case before the case is closed by its statute of limitation after fifteen years of investigating to no avail? Will Yongguk make Eunha telling him about any evidence she knows? Will he cure her mental illness and get her mind back again? Will Eunha help Yongguk to resolve the case or even… helping him to mend something lost in his life as well?