Secret Door S1:E4

Episode 1

A document, thought long destroyed, tying King Yeongjo's ascension the throne to the Noron Faction, resurfaces. Crown Prince Sado distrupts the government by proclaiming the creation and distribution of books by commoners legal.

Episode 2

Heung Bok's body is found and the conspiracy to cover-up his murder begins.

Episode 3

Unsatisfied with the result of the investigation into Heung Bok's death, Crown Prince Sado re-opens the case, personally heading it himself.

Episode 5

With Ji Dam's help, Prince Sado delves deeper into the conspiracy behind Heung Bok's death.

Episode 6

Ji Dam hides out in a brothel while Prince Sado discovers the meaning behind Jung Woon's dying message.

Episode 7

Prince Sado seeks out the identity of the man Heung Bok's final royal painting.

Episode 8

An investigation into yet another death leads Prince Sado to suspect one of the people he trusts most.

Episode 9

Prince Sado is accused of murder.

Episode 10

Teacher Park Moon Soo makes a deal to try and save Prince Sado from prison.

Episode 11

Prince Sado becomes suspicious of his father's role in the document.

Episode 12

King Yeongjo appoints a new Prime Minister and sets out to enact new tax reforms while Prince Sado struggles with what to do about his father.

Episode 13

King Yeongjo unleashes his punishment on the booklenders.

Episode 14

King Yeongjo strips Prince Sado of all governing power. Three years later, Prince Sado begins a secret plan beginning with taking Kim Taek as his new teacher.

Episode 15

In order to get his governing powers back, Prince Sado begins difficult negotiations with the Qing.

Episode 16

Kim Taek sets a plan in motion to oust and replace Prince Sado.

Episode 17

Prince Sado returns to the regency and sets out to make the country a better place for all classes.

Episode 18

King Yeongjo and Prince Sado clash over allowing commoners entrance to the civil service exam.

Episode 19

Prince Sado faces the fallout of allowing commoners take the civil service exam.

Episode 20

The Noron set a new plan in motion to oust the Crown Prince.

Episode 21

On the eve of the new Queen announcement ceremony, the Prince discovers a plot to assassinate the King.

Episode 22

The Noron set out to discover why the Prince has been sending funds to the North.

Episode 23

Episode 24