The final showdown begins as Jung Gi Joon readies for his assassination attempt against Sejong. So Yi struggles to pass down her knowledge of the Solution.

Desperate to know what the Solution is, Jung Gi Joon is willing to give up his position as a leader of Hidden Root in order to bring Sejong down.

Hidden Root falls apart as traitors abound. Chae Yun goes on a desperate search to save So Yi.

Sent out to the countryside to distribute the letters, So Yi and the other court maidens don't realize the danger lurking at their heels.

The death of Gwang Pyung puts Sejong over the brink of sanity, and the bureaucrats fear that he will become a tyrant like his father was.

Now that Sejong discovers Ga Ri On's true identity, the stakes are raised when a prince's life is on the line.

Chae Yun's mentor makes an appearance, and is immediately recruited by both Hidden Root and Sejong for his help.

The furor over an alphabet that will lead to educated peasants leads to a young scholar's suicide.

With news leaking of the new alphabet, Sejong wages an intellectual war with the scholars and bureaucrats. Chae Yun becomes a double agent.

In the process of saving So Yi, Chae Yun kidnaps the Prince and finds out about King Sejong's secret work.

The bureaucrats put greater pressure on the king to reveal his work on the alphabet, but it leads to violent results.

The king bids So Yi and Chae Yun the freedom to start over their lies together, but both of them can't forget their paths.

The destinies of So Yi and Chae Yun collide as both slowly discover each other's former's identities.

King Sejong forms a closer bond with an enemy, and opts for a scientific dissection in the hopes of helping So Yi speak again.

Chae Yun becomes suspicious of a supposed death threat against another scholar. Hidden Root leader Jung Gi Joon's whereabouts are finally revealed.

Hidden motives are revealed as different officials spring to action at the news of Hidden Root's resurrection. Sejong's mission is revealed.

Chae Yun discovers the identity of the assassin as Sejong battles his inner demons, and second guesses his mission.

Shim Jong Su gathers up allies for Hidden Root and plots the assassination for one more scholar.

Sejong breaks down at the death of another scholar, and he is the only one who holds the key to the scholar's last message.

Assigned to investigate the recent murders, Chae Yun comes face to face with an assassin with superior skills to match his own.

Ddol Bok rises to become a palace officer and changes his name to Kang Chae Yun in an attempt to get close to the king.

Sejong and his father engage in a battle of the wits as young Ddol Bok struggles to survive in the Slaves' Quarters.

Sejong's small act of defiance leads to a massacre, and an unimaginable request from his father.

Taejong, the father of King Sejong, wields his power and authority over his son to execute all his enemies, including Sejong's father-in-law.