Oh Tae-seok, the Namin political leader, frames the murder of Minister Jang Ik-hun on a secret swordsmen society. The society is led by Choi Hyo-won, a commoner. His daughter, Dong Yi works with other poor childen unloading boats. She was one of the last people to see the Minister alive

The Society is accused of murdering more political leaders. Choi Hyo-won discovers Oh Tae-seok is behind the crimes. He takes Dong Yi to a safe house but she runs away. Choi Hyo-won is framed for the murder of the police chief's father

Choi Hyo-won and his men are arrested and escorted to prison. On the way, the men are attacked and killed. Cheon-soo was tasked with protecting Dong Yi. She flees from the police officers

Chen-see puts Dong Yi in Seol-hee's care. A body is identified as Dong Yi's. The police chief knows otherwise but says nothing. Seol-hee passes Dong Yi to the head of the royal music school, Hwang Joo-shik.

Now an adult, Dong Yi is obsessed with Jang Ok-jung's ornamental key. She is convinced the butterfly shaped key could clear the names of her father and brother. She is kidnapped just as she is about to take the key

Dong Yi wakes up in a shed next to a murdered man. The police can find no body when they investigate. Lady Jang is blamed for the unpopular sound change of a musical instrument. Dong Yi meets a man who is actually the king in disguise