Mu-deok poisons Uk to open his gate
She asks Uk to risk his life for her once more, gives him a poisonous herb, and promises to be his master if he survives.

Every Alchemy of Souls moment featuring Mu-deok, in story order. Played by Jung So-min.
233 moments · 9h 09m · by Favseen
Moments 31–60 of 233
She asks Uk to risk his life for her once more, gives him a poisonous herb, and promises to be his master if he survives.
Uk collapses; the only cure is to open his gate of energy. Mu-deok is tortured but keeps silent until Master Heo opens it.
Uk wakes with his gate of energy open, finds the beaten Mu-deok, and the two finally become master and pupil.
Uk tells the Songrim leader he poisoned himself and his maid only obeyed, then refuses treatment unless Mu-deok is treated too.
Too weak to carry Mu-deok himself, Uk refuses to let Yul do it, hands her to Maidservant Kim and leans on Yul instead.
Mu-deok explains why she took the blame; Uk reveals he has been tending her himself so no mage sees her eyes, and thanks her for risking her life.
Mu-deok sets her terms: secrecy, and the bond ends once she is Naksu again. Uk accepts and vows to serve and protect her.
On the frozen lake, Mu-deok explains the three steps of a mage and relives her glory as the Shadow Assassin, until her new legs give out.
Mu-deok tests her pupil with sticks and finds no swordsmanship; Uk vows to beat his father's one-year record for Jipsu.
Asked to help with chores, Uk cites his own laziness and leaves Mu-deok fuming with a broom.
Heo Yeom sets Mu-deok to sweeping and fertilizing; she silently vows revenge, and he grabs her ear, sure he has seen it before.
Mu-deok grabs Uk to his loud protest, checks his core, and discovers Heo Yeom left a great torrent of energy in him.
To keep the energy Uk must learn Heo Yeom's breathing, used by the whole Seo family, so Yul it is. Uk gets oddly upset she won't touch Yul as easily.
Dang-gu catches them spying; Mu-deok lists every complaint about her fickle young master, and Uk pins a crush on Yul to cover it.
Taking Dang-gu's dating tips, Mu-deok shadows Yul, nimbly catching books and claiming she learned to move at the brothel.
Mu-deok follows Yul into the men's bathhouse to count his breaths, gets caught, blurts a love confession, and Yul sees right through it.
Mu-deok holds an old item of Yul's that belonged to a friend who is gone, and offers it back for his breathing technique.
Both bring back the breathing technique, the energy stirs in Uk, and he warns Mu-deok about her eyes and who she lets near.
After 99 lashes Uk refuses to leave, demands the leader deliver the last one himself, then has Mu-deok take the sword.
Mu-deok and Maid Kim worry Uk is heartbroken after his banishment, but he has been quietly practicing and vows Songrim will beg him back.
Uk's flogging makes the stolen energy surge early; his bath turns scalding then icy while Mu-deok covers with a medicinal-herb excuse.
Freezing through the night, Uk asks Mu-deok for warmth and tells her he is the egg atop the tree with only her to care for him.
Uk struggles to unsheathe the sword his father left; Mu-deok explains he needs Ryusu first and calls his stubbornness an act of vigor.
The Prince dares Uk to push him over a line; Uk takes a beating until Mu-deok's chamber-pot splash forces the Prince across it.
Uk unsheathes his father's sword but cannot control his arm; a binding bracelet stops him, and the Prince dares the four heirs to fight him together.
Mu-deok offers to drink chamber-pot water as an apology, Uk insists he should, and the friends join in until the Crown Prince gives up.
Mu-deok hands the Prince Naksu's sword with lavish flattery so he can call himself the winner; he gives her a new nickname.
Mu-deok explains why she splashed the Prince and turns down a handkerchief from the man she claims to love.
Uk shows the Songrim leader he can now draw his father's sword and begs to be taken in, but unbound, his arm cannot hold the blade.
Mu-deok tries to rouse Uk to train after only ten days of progress; he refuses and tells her to just be his maid.