In Alchemy of Souls Ep 12, Jang Wook lost his eighth duel, but he was able to improve his skills. After seeing Jang Wook’s wounds, Mudeok became emotional and asked him to get treatment. In the meantime, Jinmu succeeded in performing alchemy of the souls on Master Kang and his disciple. He, along with Master Kang, killed his disciple, to whom he shifted his soul.
After hearing about the passing of Master Kang, Park Jin rushed to his funeral but was restricted from attending it by Master Kang’s pupils, stating that they wanted to keep the master’s cause of death secret from the general public as they didn’t want the public to know that he was killed by assassins.
As a result, Park Jin’s suspicion grew stronger that it was a matter of sorcery. He again showed up at the cremation of Master Kang and secretly ordered Yul to check the blue mark on Master Kang’s body, and if he found the mark, then cast a spell on him so that he would run wild and turn stone. As planned by Park Jin, Master Kang’s body turned into stone after the cremation ended, and he proved this to Jinmu and told him that Master Kang’s death happened as a result of sorcery, so Songrim will investigate this case.
After seeing the severity of the matter, Master Kang’s disciple became enraged and pointed a sword at Park Jin, but was defeated by him and turned wild. Jinmu ordered his men to kill the soul shifter, and Park Jin asked Yul to protect him so that they could investigate better, but the soul shifter was nearly killed.
Park Jin asked his men to take the body to Songrim, where they treated the soul shifter secretly, but Jinmu became suspicious that the soul shifter was still alive, so Park Jin asked all the mages except Jang Uk to actively take care of Sejukwan, where the soul shifter was being treated.
Park Jin told Jang Wook to stay away from this matter and that he could go home and rest. Mudeok was told to run an errand by Kim Do-ju to deliver honey biscuits to Cheonbugwan. When Mudeok was leaving for Cheonbugwan, she encountered Jang Wook, who told her that he would come along with her. Jang Wook and Mudeok delivered the sweets to the Cheonbugwan gate men. Jang Wook and Mudeok entered Cheonbugwan, saying they wanted to see it from inside.
At the time, Jinmu was trying to kill an eunuch who threatened the Queen by revealing her identity as a Shaman in the Queen’s body if she didn’t ask Jinmu to shift his soul into a young and powerful body. Jang Wook and Mudeok noticed the royal eunuch fleeing and Jinmu pursuing him. Jang Wook, who was hiding, came in front of Jinmu and pretended he didn’t see anything and told Park Jin that he came to deliver sweets.
Jinmu thanked him and asked him to leave. Jang Wook told him that he was not alone but that his maid, Mudeok, was hiding because he thought he would be angry seeing them inside Cheonbugwan. Jang Wook and Mudeok were leaving, and suddenly Mudeok slipped, which made Jinmu suspicious of them seeing a soul shifter, so he closed all the doors and held Jang Wook prisoner in his spells, creating an illusion. Jinmu told that soul shifter to feed on Mudeok and told him not to be afraid of him because he was leaving so that he could feed as much as he wanted and left the place.
At the end of Alchemy of Souls Ep 12, Mudeok was trying to protect herself from that soul shifter, and she started to run but was captured by him. Jang Wook, on the other hand, broke the spell and freed himself. As soon as he found Mudeok, he saw Mudeok absorbing the soul shifter’s energy. When Mudeok came to realise that she had run wild and absorbed someone’s energy, she asked Jang Wook to stay away from her and not to touch her, but Jang Wook consoled her by hugging her.