Episode 4 boasts of a jump in viewership ratings, with a recorded 6.1% and 5.2% for its two parts. The previous episode’s events were on a steady rise for the upcoming episode’s climax. Sung Yi-gyum (Kim Myung-soo) proves just how dangerous being a secret agent is, being at death’s door twice in just one episode. Meanwhile, Hong Da-in’s (Kwon Na-ra) growing admiration for Yi-gyum continues to bloom.
Sung Yi-gyum saves Hong Da-in from death
As Da-in runs for her life, Yi-gyum waits for an opening to strike the enemy. As he engages Kang Jong-gil (Han Jae-suk) and his men in a fight, Park Chun-sam (Lee Yi-kyung) arrives and intervenes, with the sheriff (Choi Jong-won, Mr. Sunshine) behind him. However, instead of helping them, the sheriff has all three of them arrested. Both Yi-gyum and Chun-sam are to be sent to the mining field to be slaves, but Da-in is to be killed for tricking Jong-gil. As a desperate attempt to save her life, Yi-gyum bargains information for the whereabouts of the sheriff’s newly born grandson, Jong-gil’s child with Sa-wol (Kim Ju-young, Mr. Queen), in exchange for sparing Da-in’s life.
Political turmoil in the palace
Back in the palace, the conniving officials continue their attempts to abolish the agent system. But the Palace soon receives a letter from Yi-gyum’s party, informing them of Park Cheol-gyu’s (Kim Seung-soo) tragic death as well as the perpetrators behind it. Enraged, the King (Hwang Dong-joo) immediately sends his men to arrest the sheriff, his son, and the others involved.
Sung Yi-gyum and Park Chun-sam are sent to the labor camp
Before Yi-gyum and Chun-sam get separated from Da-in, Yi-gyum instructs her of a plan to save herself and Sa-wol’s child, as the sheriff intends to kill both of them. Da-in obliges, leading the sheriff’s men to an ambush with one of the Palace’s trusted royal guards Choi Do-kwan (Shin Ji-hoon, Love with Flaws). Meanwhile, inside the camp, Yi-gyum and Chun-sam listen to the other slaves’ cries for injustice, including Sa-wol’s brother Dong Soo (Park Jun-mok, Into the World Again).
Hong Da-in invades the slave camp
Disguising themselves as merchants, Da-in and Do-gwan successfully enter the labor camp to rescue Yi-gyum and Chun-sam but are quickly subdued by the enemy. However, Da-in’s plan of disarming the guards with the spiked drinks worked, and they proceed to free the slaves in the prison. However, Jong-gil suddenly arrives at the camp, and the two parties clash. To escape, Jong-gil holds Da-in hostage, and Yi-gyum pursues them. In an attempt to flee from Yi-gyum, Jong-gil pushes Da-in off a cliff, and while Yi-gyum tries to pull her from her nearing demise, Jong-gil aims his sword at Yi-gyum.