Go Won confesses his regret over Naksu in Gwido
Searching for the plaque, Go Won asks for the blue jade back, then admits he wanted Naksu and is ashamed; Bu-yeon tells him to hurt, then let go.

Every Alchemy of Souls moment featuring Crown Prince Go Won, in story order. Played by Shin Seung-ho.
99 moments · 4h 06m · by Favseen
Moments 91–99 of 99
Searching for the plaque, Go Won asks for the blue jade back, then admits he wanted Naksu and is ashamed; Bu-yeon tells him to hurt, then let go.
At the secret gathering of soul shifters, Go Won questions what happens to those who lose their bodies, then declares he stands with Jang Uk.
Uk traps the secret room in a barrier and fights every soul shifter, telling Jin Mu he came to do what is right, not for revenge.
Bu-yeon reports Jin Mu's fate; the officials realise she could remove Uk's ice stone and vote for it, and she agrees to obey.
Go Won learns a soul shifter in the palace is Jin Mu; the King sides with him and takes away the Crown Prince's Gold Plaque.
Songrim mourns Jin Ho-gyeong, Maid Kim and Park Jin with empty coffins, until Master Lee says the three did not die after all.
Uk gives Go Won a plaque left by the late king so he can stop the army, and says he already reached the peak with the one he loves.
The King waits for his guards, but Go Won has countermanded the order with the Gold Plaque of the man born under the King's Star.
Master Heo plots to make his granddaughter queen; gossip says the new King practices chastity, and the King recalls a turtle son.