Waking in an abbey, Nimue finds herself surrounded by strangers and forced to tend to Red Paladins. Arthur sets out on an adventure of his own.
- Arthur has a flashback of witnessing his father's death after he was injured in a fight. His father asks him to bring back their honor.
- Nimue wakes to a girl watching her sleep. Her sword is gone. Morgana gets rid of Sister Iris by telling her she left food for her in the kitchens.
- Abbess Nora discovers that Nimue is in the convent and tells her that she can help in the infirmary. The Red Paladins have brought an injured paladin to the convent to be treated. The nuns there know that if they let him die, they will die too. The man that they have to heal is one of the men that Nimue attacked with her magic, and he has branches growing through his body, as well as a burn where he was cut by the Sword of Power. The three markings are supposed to mean water, earth, and fire; the same markings are on the pommel of the Sword. Nimue and Morgana use Fey methods to try to heal him, though this is forbidden.
- Merlin meets with Brioni, who tells him to go away, saying that Rugen knows he's there and doesn't want anything to do with him. Merlin tells her to tell him that he brings gifts.
- The Weeping Monk tells Father Carden that the enemy is at the convent, because he can smell their Fey scent.
- Nimue threatens a nun so that she can take her jug and go into the room where the Red Paladins are talking about their plans to recover the Sword of Power. Nimue listens in.
- Arthur goes to Gramaire and finds his Aunt Marion, asking her to help him speak to his uncle about representing him in the tournament. Marion gives him a tunic that her late son Charles wore.
- A flashback shows that after Arthur's father died, Morgana was placed in the convent so Arthur could work off his father's debt without worrying about Morgana.
- Abbess Nora lies to Father Carden and tells her that there haven't been any new additions to the convent that week. Father Carden and the Weeping Monk make the nuns gather so they can question them. Iris reveals that there has been a new addition to the convent so they go looking for Nimue.
- In his castle, King Uther Pendragon speaks with his mother, Lady Lunete. When she will not speak to him at first, he accuses her of putting on a performance. She tells him he only comes back when he wants something from her, warning him that Merlin is up to something.
- Nimue catches Celia and Morgana kissing. Morgana threatens her, but Nimue says that she won't tell anyone because they haven't done anything wrong.
- Nimue takes some of the papers, lists, and maps that the paladins had been looking at and burns them.
- Arthur lies to Lord Ector about how he got the Sword to get on his good side. This ruse is ruined by Bors, whom Arthur used to work for. Bors wants Ector's rings as payment for the debt Arthur owes him. Arthur and Bors get in a fight and Arthur kills one of the men, causing him to lose Ector's respect. Arthur is captured and the Sword of Power is taken away from him.
- The Widow tells Merlin that she's had a vision of his suffering and that she doesn't want to help him.
- Morgana helps Nimue escape via a small boat, knowing that she is the Fey girl that the Red Paladins are looking for.
- Katherine Langford as Nimue
- Devon Terrell as Arthur
- Gustaf Skarsgård as Merlin
- Daniel Sharman as The Weeping Monk
- Sebastian Armesto as King Uther
- Lily Newmark as Pym
- Shalom Brune-Franklin as Igraine
- Rafi Fraser as Young Arthur
- Freddie Hawkins as Shortshanks
- Richard Pepple as Sir Tor
- Alice McMillan as Sobbing Barmaid
- Manvir Bawa as Boy 1
- Rico Canadinhas as Boy 2
- Emily Coates as Iris
- Richard Brake as Brother Theophilius
- Caroline Lee-Johnson as Abbess Nora
- Bryony Miller as Brioni
- Gabriel Akuwudike as Ortho
- Joel Morris as Keth
- Siu-see Hung as Sister 1
- Terence Maynard as Brother Salt
- Frank Miller as Brother Horde
- Jaye Griffiths as Lady Marion
- Dermot Keaney as Collector
- Isabella Austin as Young Morgana
- Peter Guinness as Sir Ector
- Polly Walker as Lady Lunete
- Sophie Harkness as Celia
- Gary Reimer as Red Paladin 1
- Zoe Waites as The Widow
- David Verrey as Sir Boone
- Sean Gilder as Bors
- David Gant as Magistrate
- Antonio Magro as Elliduc
- Sir Tor, to Arthur: Bring back our honor.
- Weeping Monk: The enemy is here.
- Morgana: How long were you there?
- Nimue: Long enough.
- Morgana: Well, you don't know what I can do to spies.
- Nimue: I won't tell anyone. Not because I'm afraid of you, but because you've done nothing wrong.