Lady Coroner in Joseon
Aran with a wounded heart becomes a coroner
Aran pretends to be an illegitimate daughter of the mayor of Hanseongbu (present-day Seoul) who killed her parents. Seeking revenge, she becomes a coroner to collect evidence, and examines bodies day and night to determine the causes of death. One day, an incident shocks the entire city—six bodies are found in a burning cave on Mt. Mongmyeok. Aran investigates the case with Yuno, the inspector from Saheonbu (Office of Inspector General), and Hanseok, the judge from the Office of Hanyang (also Seoul), but the truth remains uncertain. Later, one of the bodies turns out to be that of Heocheong, the only son of the minister of war. Now, all eyes turn to the capital. Aran risks her identity being revealed to focus on the investigation and realizes that Heocheong is the key.
Rumor and truth of the Mt. Mongmyeok incident
While the investigation goes through a difficult period amid the silence of the bereaved and those involved, a strange rumor spreads throughout Hanyang that there is a puppet show about the murderer. Aran, who has reached a dead end, immediately heads out to Mt. Mongmyeok, where the show was performed. There she learns that Heocheong used Seungyeosa (an affiliated institution under the Ministry of War) to commit human trafficking and killed the rest of the five victims. She quickly heads backstage to see the performer, but the area is already empty. That is when she is hit on the head and passes out.
Hide the evidence vs find the evidence
The Minister of War tries to get rid of all the evidence and the witnesses to hide his son’s crime, and for some reason, the mayor cooperates. Aran fights to unveil the truth and bring justice, but instead, faces a severe crisis. In truth, the mayor had his own agenda when he accepted her as his illegitimate daughter, and now, she was no-longer of any use to him. She is soon placed on the wanted list, and it is the mayor himself who framed her for the murder.
Truth behind the truth
Aran has an audience with King Sejong to clear the false charge. She successfully proves her innocence with physical evidence and witnesses, and the king orders the arrest of the Minister and the Mayor. However, Aran has yet to prove that the mayor killed her parents. While experiencing a conflict of interest between personal revenge and legal punishment, she finds out that the performer of the puppet show was the person who killed Heocheong. And it was someone she has never imagined it to be! The truth is out there now. Can she still maintain her faith?