![](https://image.tmdb.org/t/p/original/qKfMxlzR95eDqvV3r5XrEVEpUUf.jpg)
![](https://image.tmdb.org/t/p/w342/ko46oHoWmGWYaWMPZM931Cjv1YK.jpg)
Dong Yi Discovers The Cause of the Plague
Jang Ok Jeong finds out that it is her mother who causes the plague. She however ignores it because of her hate towards Dong Yi. In the meantime, Southern Faction finds no early records about Dong Yi and Cheon Soo. So, they try to get the information from Dong Yi's friends. Dong Yi meanwhile discovers that the plague is caused by the poison in the cosmetics that are linked to Jang Ok Jeong's mother. But, she is arrested because her three days limit is over. The King has been informed about the investigation and when he goes to question Jang Ok Jeong, she says that she and her mother know nothing about it. Then, delegates from Qing are coming to acknowledge the Crown Prince.
![](https://image.tmdb.org/t/p/w300/xqfacS8cSBy0upWiC9uunfnDAxc.jpg)
Other episodes for this season
![The Start of a Tragedy](https://image.tmdb.org/t/p/w300/PpsMH6M3Kbs7yvPEzPLOZQo5rs.jpg)
![The Framing of Sword Fraternity](https://image.tmdb.org/t/p/w300/u3MJzhiA0Y5AvkGyiSoRBkVlWgF.jpg)
![The Rescue Mission](https://image.tmdb.org/t/p/w300/1lqoMSmN9hagUG6zQl0J93RhO9O.jpg)
![The Search for the Truth](https://image.tmdb.org/t/p/w300/pxtFyCOzke1z2wxDQyF0xAN7mEg.jpg)
![A Bad Omen](https://image.tmdb.org/t/p/w300/dfdQD4yorrqVRrzwk9EtkhsBerV.jpg)
![The Investigation](https://image.tmdb.org/t/p/w300/2cvzhe3GfPnhsqnpACJAqG6Ore6.jpg)
![The Plan That Backfired](https://image.tmdb.org/t/p/w300/mNykWtrxJQvcs9oqm4L9tlFOvBL.jpg)
![The Medicine](https://image.tmdb.org/t/p/w300/y9xgxc72wgCmN317UXTcXrIN5ft.jpg)
![The Confession By Jang Ok Jeong](https://image.tmdb.org/t/p/w300/veT7jFz0ygN8NVMg9ubSWgeKpqb.jpg)
![The Evidence](https://image.tmdb.org/t/p/w300/qg3TP2I4hiQJBOUD3L3P3WXPdXt.jpg)
![The Truth Revealed](https://image.tmdb.org/t/p/w300/h0ddHZAq7nWnRpQuyHC3hYB8hnU.jpg)
![Dong Yi Becomes a Court Lady](https://image.tmdb.org/t/p/w300/AjzxRule04k8eempvCDGyF3Fgex.jpg)
![The Sword Fraternity Headband](https://image.tmdb.org/t/p/w300/7TVTfpuonoyfUtwK0B1AQljRqeN.jpg)
![Dong Yi and Chun Soo Reunited](https://image.tmdb.org/t/p/w300/dDhVLNKxjlSVhP3m9kA4mzQ9M79.jpg)
![Dong Yi Turn Herself In](https://image.tmdb.org/t/p/w300/tzXi2A1E4D1D9uoz4Mc4yuYrq0.jpg)
![The Truth About Joseon Smuggler](https://image.tmdb.org/t/p/w300/nCHyCEAkkx1Xd7rvnqyVgO54EjO.jpg)
![Jang Ok Jeong Pregnancy](https://image.tmdb.org/t/p/w300/kbwnNt0HxMusoKtJZF0sgLQV3gT.jpg)
![The Queen Dowager Poisoning Scandal](https://image.tmdb.org/t/p/w300/iNxBUJt5sanRNeIT9yqwbI58RBG.jpg)
![The Conspiracy](https://image.tmdb.org/t/p/w300/kmXPL8i3wnAU8BXy6vKC1CFK9fh.jpg)
![The Death of Queen Dowager](https://image.tmdb.org/t/p/w300/uqIm8CnATCJr3vzPUBU9BE9FMGf.jpg)
![The Queen's Dethronement](https://image.tmdb.org/t/p/w300/t8YfFQPJDcnDBFUMxxFuEUb7H4v.jpg)
![The Audit](https://image.tmdb.org/t/p/w300/j5lBcK6iV31FphaicGoEt72Aev9.jpg)
![The Assassination Attempt on Dong Yi's Life](https://image.tmdb.org/t/p/w300/4z6Wm9ye6LCHob0V7PWxuqVNDAn.jpg)
![The Disappearances of Dong Yi](https://image.tmdb.org/t/p/w300/aLwvC2GPXytn8nTZOiBL0t51jrM.jpg)
![The Exiled Nobleman](https://image.tmdb.org/t/p/w300/vgkB4OWPW2aJkGRpMblpPQpveWe.jpg)
![National Security Records](https://image.tmdb.org/t/p/w300/lXI2ZL08Zb2dzkoESgQSeFSGCCW.jpg)
![The Dangerous Plan](https://image.tmdb.org/t/p/w300/1yfNzbKinoODvOI5GzBSeilO7yH.jpg)
![The Melody](https://image.tmdb.org/t/p/w300/tQsXlxKOIDmR0uEJeEhQSK8cnQ4.jpg)
![The King and Dong Yi Are Reunited](https://image.tmdb.org/t/p/w300/zJlvXhwG04fGV3o8Fi4eO5ZuVKb.jpg)
![A Special Court Lady](https://image.tmdb.org/t/p/w300/y1Bu2FcDjPh8frkg46Ll7p6ktJW.jpg)
![The King Confess His Love](https://image.tmdb.org/t/p/w300/gNS9icbtL4bbgTEdcI3yNLRx5X.jpg)
![The Plague](https://image.tmdb.org/t/p/w300/h0QBlmWL16EGBa5ZsBNuyOoqVrf.jpg)
![Dong Yi Discovers The Cause of the Plague](https://image.tmdb.org/t/p/w300/qKfMxlzR95eDqvV3r5XrEVEpUUf.jpg)
![Dong Yi's Secret](https://image.tmdb.org/t/p/w300/5yEGWNa5Qj7eiZk7mJPi0j8TJPZ.jpg)
![The Plan to Search For Security Records](https://image.tmdb.org/t/p/w300/1WphTdPAqQwwt3NHoxAPW6EjV84.jpg)
![Dong Yi's Trap](https://image.tmdb.org/t/p/w300/qYWFNjijHYhAX67VECCWcskgKBS.jpg)
![Jang Ok Jeong's Dethronement](https://image.tmdb.org/t/p/w300/gCLFsa0vIjMvbcivZfR6GjxRdJr.jpg)
![The King's Dream](https://image.tmdb.org/t/p/w300/7eBCy9M1RjXygNHPUdvL02DlsCV.jpg)
![A Year Later](https://image.tmdb.org/t/p/w300/ldpCaQDVsIUy6ezLAGWCdCJ0xuR.jpg)
![Sword Fraternity Regrouped](https://image.tmdb.org/t/p/w300/v4nzIVKwFNyqwURLkiWGEusEqGW.jpg)
![The Hand Signals](https://image.tmdb.org/t/p/w300/sE8u4BJrpJghK0tcUn8VQ7eX4WP.jpg)
![Oh Tae Seok's Murder](https://image.tmdb.org/t/p/w300/nq1MhV18ZLPQIQLSmBMzzlAV5Ts.jpg)
![King's Cover Up](https://image.tmdb.org/t/p/w300/gZD9HlaOkoo4Wp5Q5Eh426eNVFo.jpg)
![Dong Yi's New Son](https://image.tmdb.org/t/p/w300/cQr36qNpssluUz7vkC1eUfMADbM.jpg)
![King Sukjong Meets His Son](https://image.tmdb.org/t/p/w300/vXGwhEEVDYi6Bl9dqpNRulIifo8.jpg)
![Dong Yi and Her Son Come Back to The Palace](https://image.tmdb.org/t/p/w300/4tiEQFCtroqoebphyEXz7oTbKBT.jpg)
![Child Prodigy](https://image.tmdb.org/t/p/w300/fgoBAUKYRqsJwdgWEwgaiUBlzg5.jpg)
![The Plot to Kill The Queen](https://image.tmdb.org/t/p/w300/pxnUdhswR40eqE6DNbjI3UFf8wt.jpg)
![The Death of The Queen](https://image.tmdb.org/t/p/w300/ArsVNMHhnngmF2ZO557c64rR8Sh.jpg)
![Dong Yi Promotion to Bin Level 1 Concubine](https://image.tmdb.org/t/p/w300/nXRD1YKgENIsXXbsGb2VAS1cNKg.jpg)
![The Crown Prince is Missing](https://image.tmdb.org/t/p/w300/aCvk96orYFqnmZGxVEZROJEAyx.jpg)
![The Truth About Crown Prince Illnes](https://image.tmdb.org/t/p/w300/vQH6q7h2eKRavEI97oRLl3TjQtv.jpg)
![The Attempt to Kill Prince Yeoning](https://image.tmdb.org/t/p/w300/xbAFZZfPf26RwhDj0nDkyzo8Ro.jpg)
![Jang Ok Jeong's Family Sentences to Death](https://image.tmdb.org/t/p/w300/iA3Vw9lrQ09HPeRxlPcbCuOK3yp.jpg)
![Jang Ok Jeong's Execution](https://image.tmdb.org/t/p/w300/kPQBLQCj8qM0kPB3MExjG5tsbeu.jpg)
![Prince Yeoning's Marriage](https://image.tmdb.org/t/p/w300/pagINJCa8xsDJDjI9XeFcxJRrfs.jpg)
![The King Contemplates to Abdicate](https://image.tmdb.org/t/p/w300/Hdy4fbgfFZZiUXzcoGmrZQirYn.jpg)
![Jang Moo Yeol's Plan to Frame Dong Yi and The Prince](https://image.tmdb.org/t/p/w300/ffixQfD5By8C03aUFinKWbIZzLN.jpg)
![Jang Moo Yeol Executed for Treason](https://image.tmdb.org/t/p/w300/b6okT5ka6PgmQ6FzeZyKUOIn53F.jpg)
![A Happy Ending](https://image.tmdb.org/t/p/w300/bj7VhBrxxClBlNzuBSjy5jXAhOi.jpg)