"Are you working for Hawgidogam (a national R&D organization for firearm)? I heard that the King is great on gunpowder development. That means... you work for Gwanghae (Cha Seung Won), right? " Hwai (Lee Yeon Hee) sounds him out to see if he's not undergone a personal transformation.
Hong Joo Won (Seo Kang Joon) stands in silence with an expression of mixed feelings.
One of the King's concubines throws a decoction bowl on the floor saying that she knows why the other eight women haven't produced child. Kim Gae Shi (Kim Yeo Jin) orders a female attendant to decoct the medicinal herbs again.
"I am just one of attendant. But you should listen to me in the palace if you already knew what o'clock it is." she calmly answers.
She also answers coldly, "Her Majesty the Queen! It's a mercy there is no child without the only crown prince." to the Queen who has her doubts about the decoction.
Gwanghae makes a decision to go to the area of Ming border to supply new weapon for subjects. Yi ICheom (Jung Woong In) is not sure what brings him to such a humble place although he leaves the palace empty for a long time.
"Are you afraid? Never let others know you do. The king should focus on only what you really want thinking what you should do with it in the future." he tells the crown prince before he goes up north as if he beats himself up.
Meanwhile, Queen Inmok (Shin Eun Jung) stays away from the royal progress not to forget his face until she takes back power enough to eliminate the political opponent.
Hawi asks Marno, the sulfur mine owner, to let Hong Joo Won meet Idachi (Ryohei Otani), a business magnate and sulfur smuggler. He knows Hawi tries to run away to Joseon, but he decides to help the slave who have played a large role for his business until now. Eventually, Joo Won and Jeongmyeong close a business deal with the wealthy merchant.
Hawi walks around the market with Hong Joo Won because he has to write unique Japanese custom down as a member of Joseon Tongsinsa. Her face clouds over when she recalls his words, "I'm Hong Joo Won working for Hawgidogam in Joseon," "It's a matter of the security of Joseon and the King."
Gwanghae runs at full speed along the narrow mountain path in the middle of the night. A group of volunteers swear allegiance to the King who asks them to undertake an highly dangerous mission.
Kang Joo Sun (Jo Sung Ha) is informed about the sulfur traffic and he orders his man to have their offense detected.
Gwanghae escorted under the armed guards looks down a Ming's military camp. The King orders them to extricate a man without big trouble. After a bitter fight with swords, the King looks back at calling him.
Heo Gyun (Ahn Nae Sang) hands a 300-year-old writing of divination missing from Joseon to the King.
Hawi leads Joo Won and other guards to a ferry for the traffic in sulfur. But they are caught in the act of the illicit traffic.
She takes Joo Won hostage threatening him with a knife, "I will take your blame on myself. Tell them you also sucked in by me. You will be fine because you are Joseon delegation. You have to save me because I have to go to the country."
She throws the knife away.
Joo Won felt suspicious about his direct subordinate runs him to earth. He finally disclose the fact that Gwanghae made him to keep a close watch on the illegal transaction to expose a plot of a mastermind reigning over the King. Joo Won cannot repress his astonishment.
Princess Jeongmyeong, who is jailed in a prison, is waiting for Joo Won to save her fiddling with the bracelet from her mother.
"You have to keep the promise this time." she mutters to herself looking out of the window.
Meanwhile, Ja kyung (Gong Myeong) grabs the official by the collar criticizing him severely.
"He made this happen. Follow me. Aren't coming here to save her? I need your help. I will surely save her as I promised." Joo Won speaks with finality.