Outside Camelot, Merlin and some other peasants are collecting wood. Several bonfires burn in the forest, and Merlin sits down on a log for a rest, noticing smoke billowing out from a nearby fire. Looking a little lonely, Merlin mutters a spell and smiles as the smoke takes on the appearance of a galloping horse. Merlin watches for a while, and then lowers his hand. Just as he begins his work again, a woman runs up to him in terror. She witnessed the smoke-horse, and despite Merlin's protests, she rushes off to tell the King.
In the throne room, Uther listens to the woman's claims. Merlin squirms a little under Gaius's disapproving side-long glance, and is visibly exasperated when the woman says that she feared for her life. Uther thanks her for bringing him the news, and decides to call in the Witchfinder. This announcement causes a stir among the court.
Down in the physician's quarters, Gaius is scolding Merlin for his carelessness (though he himself is currently not being particularly quiet about the fact that Merlin has magic). He warns him about the man that Uther has sent for - a dangerous man called Aredian who he describes as "a force to be reckoned with." Merlin tries to crack a joke, but Gaius is not at all amused.
By night, a large horse-drawn cage rattles into the courtyard of the castle. An intimidating man in dark clothes
and a wide-brimmed hat
jumps down from the driver's seat. And if none of that is scary enough, it turns out that he's played by Charles Dance
. Yeah, that
Charles Dance. Be afraid. Morgana watches in terror from her bedroom window, looking especially horrified at the sight of the cage.
Uther and Arthur are discussing Aredian in the Council Chamber when they are interrupted by an ominous voice:
Aredian: Do you smell it? Do you smell it, Uther?
Aredian: It's all around us, the foul stench of sorcery. It's infected your great city like a contagion.
Uther: I welcome you to Camelot, Aredian. Thank you for making such haste to be here.
Aredian: Well, let's hope I'm not too late, hmm? For every hour counts in the war against sorcery. Unchecked, it spreads like a disease. It seeks out the young and the old, the weak and the able, the fair and the foul of heart alike. You've grown lazy, Uther. You've grown idle. Your once noble Camelot is rotten to the core. You stand on the brink of dark oblivion.
Arthur introduces himself and offers the services of his knights, but Aredian is quick to dismiss him from the investigation. Uther reassures Aredian that he will pay whatever price is necessary to rid the kingdom of magic.
The following day, Aredian confronts Gaius and Merlin in the lower town. He has recognised Gaius, and insinuates that he knows about his past. Gaius reluctantly introduces Merlin, and Aredian requests his presence for an interview later in the day. Merlin nervously agrees.
In Aredian's quarters, Merlin eyes a skull ink-well on the desktop nervously as Aredian grills him about what he saw in the forest. Despite the woman naming him as a witness, Merlin denies ever seeing a horse appear in the smoke. Aredian increases his nerves by stating that either the woman is lying, or Merlin himself conjured the vision, and states that their conversation is over...for now.
Some time later, Aredian presents three women to the court. Uther listens in growing horror as they recount the terrible things they've seen: screaming faces in the well, a goblin dancing on the coals, and a sorcerer with toads jumping out of his mouth. All the women seem legitimately terrified, and Merlin whispers to Gaius that he's not responsible for any of it. Aredian announces that he has already found the guilty party. Morgana sits in her seat, almost frozen with terror. Aredian dramatically points to Merlin as the culprit. In the stunned silence that follows, a single incredulous voice speaks out:
In the crowd, Gwen pulls a confused face. Merlin replies that he has nothing to hide, and Aredian orders a search of his rooms.
Lead by Sir Leon, the physician's quarters are nearly torn apart in the guards' zealous search to find evidence of witchcraft. Leon breaks a powder jar and discovers a strange-looking bracelet. Aredian identifies it as an amulet of enchantment and orders Merlin's arrest. Gaius speaks out, claiming that the amulet belongs to him.
Down in the dungeons, Arthur frees Merlin from the cell and tells him he's free to go. On his way out, Merlin passes Gaius being lead into the cell, who demands that he say and do nothing. Returning to the physician's quarters, Merlin is devastated to see the condition it's in, and slowly begins to try and clean it up.
Over dinner, Uther makes an attempt to defend Gaius, citing his many years of loyal service. Arthur is sceptical at Aredian's claim that Gaius once practiced sorcery, but Uther confirms it, though he had been led to believe that those years were behind Gaius. Aredian suggests that he's fallen back into old habits, and Uther reluctantly agrees to his "methods".
Gaius is awoke from slumber by having cold water thrown over him. Aredian looks pleased at his discomfort, even as Gaius tries to explain that the amulet was only an old keepsake from the past. A montage begins in which Gaius is relentlessly grilled over his past and his opinions on magic. Finally he asks for a drink of water, though Aredian tells him he will only get one if he confesses to the crime of practicing magic. Gaius refuses.
Watching Gaius getting dragged from the interrogation room to the cell, Merlin hurries down to seek the counsel of the Dragon. He is unimpressed by Gaius's plight, and tells Merlin that his stupid behaviour will only continue if he confesses to being a sorcerer in order to clear Gaius's name. If he confesses, the Witchfinder will simply have them both executed. Seeing no way to aid Merlin, the Dragon simply flies off.
Getting increasingly frustrated at Aredian's methods, Gaius reels off a litany of the services he has done for the king, and accidentally lets slip that he has treated Lady Morgana. Aredian latches onto this instantly, and realizing his mistake, Gaius tries to downplay her nightmares. But the damage has been done, and Aredian decides to question her next.
Gaius watches in dismay as Morgana is brought down into the dungeons for questioning. The two exchange nervous glances as Morgana is lead into Aredian's workroom. He pointedly hangs a torture device on the wall next to her before settling down to ask his questions. Morgana gazes at it in horror as Aredian asks her whether Gaius has ever treated her for nightmares. She answers in the affirmative, and looks profoundly relieved when he lets her go. Just as she's at the door, he calls her back. Catching her off-guard, he asks whether she knows what was in the potions that Gaius gave her, and whether her nightmares have gotten better or worse since taking them. Either too nervous to lie, or seeing an opportunity to turn Aredian's attention away from her, Morgana states that her nightmares have gotten worse since Gaius's treatment.
The following morning, Aredian pokes Gaius until he awakens, informing him that Merlin and Morgana will be joining him in the flames. Unless of course, he and Gaius can come to a deal...
Gaius is brought before the court and forced to kneel before Uther.
Gaius: I...I am a sorcerer, Sire. I am responsible for conjuring the smoke. I'm guilty of practicing magic in Camelot, the goblin, the faces in the well, I...I am the sorcerer who conjured the toad from his mouth.
Uther: You've betrayed me, Gaius. Betrayed your friends. And above all, you've betrayed yourself. By the laws of Camelot, I must sentence you to death.
Aredian: The sorcerer will be purged of his magic by means of fire! He shall be burnt at the stake tomorrow at dawn! Bear witness and heed this lesson!
Gaius is dragged from the room by the guards. Arthur, Gwen and Morgana watch in dismay, but Merlin charges at Aredian, accusing him of lying. Instantly Arthur leaps from his chair and intercepts Merlin, half-pushing, half-dragging him from the room. As soon as they're outside, Merlin tries to punch him, but Arthur twists his arm behind his back. It turns out that Arthur isn't trying to throw him in prison, but give Merlin a few minutes to talk to Gaius.
Merlin and Gaius hug within the dark cell, and soon the truth about the amulet comes out: Merlin thought that it belonged to Gaius, but he was lying in order to cover for Merlin. They deduce that Aredian put it there, and Merlin realizes that if he can prove it, then Gaius will go free. Gaius begs him not to get into any more trouble, but on seeing the pyre being built in the castle square, Merlin knows he doesn't have any choice.
Aredian returns to the dungeons once more to taunt Gaius with the fact that his investigations have just begun. Despite the fact that Gaius confessed to witchcraft in order to spare Merlin and Morgana, Aredian still intends to incriminate them.
Morgana is watching the pyre being built from her bedroom window, and swivels around in fright as Aredian appears behind her.
As night falls, Gwen bursts into the physician's quarters to find Merlin. Morgana is being questioned, and Gwen can tell that she's being worn down. Merlin confirms that this is how Aredian operates: he breaks a person down until they can't help but confess. He tells her that Aredian planted the amulet in Gaius's study, presumably to collect the reward money that he gets every time he extracts a guilty confession. They realize they need proof.
Merlin sneaks into Aredian's quarters, and magically unlocks a cupboard. Inside is a jar of flower petals. Merlin pockets a couple just as he hears the sound of footsteps approaching. Aredian enters the room and looks around suspiciously. He walks over to a drape and yanks it back, only to discover that no one is there. Merlin watches from under the bed as Aredian leaves the room.
Back down in the physician's quarters, Gwen and Merlin are flipping through the pages of Gaius's books, looking for a depiction of the flower petal. Finally Merlin discovers that it's belladonna, and that it can cause the onset of hallucinations. That sounds promising, but they realize that Aredian would be too clever to give it to the witnesses directly. Gwen recalls that all the witnesses were women, deducing that whatever gave them the visions was something that would only be used by women. In a flash, she realizes what it was.
Merlin and Gwen race through the lower town and bang on a door. An older man opens it, wondering what they're doing in the middle of the night. The two friends shoulder their way into the apothecary shop, and demand to know whether he's selling a tincture of belladonna. The apothecary tells them that it can be found in his range of eyedrops, which women use to brighten their eyes
. The mystery solved, Gwen coaxes a confession out of him: that Aredian gave him the eyedrops to sell.
Back in the physician's quarters, Merlin grabs the tincture from the apothecary and the flower petals, stating that along with their witness, they've got everything they need to expose Aredian. But Gwen isn't so sure - after all, it's only the word of three lower-class citizens against Aredian. They need irrefutable proof; something that even Aredian can't deny. Getting another brainwave, Merlin rushes from the room.
Back up in Aredian's bedroom, Merlin tiptoes past the sleeping man and whispers an incanation over the cupboard. As he sneaks out, he gets another idea, and doubles back in order to whisper a spell over Aredian as he slumbers.
Elsewhere, both Gaius and Gwen watch with dread as the sun rises. Merlin bursts into the room and Gwen informs him that Gaius has already been taken from the dungeons. Now they have to delay the execution, and decide to go to Arthur. Seeing how wound up Merlin is, Gwen asks that she be left to handle Arthur.
Gaius is taken to the pyre in Aredian's horse-drawn cage. Uther watches guiltily from the balcony, whilst Arthur stands among the crowd surrounding the bonfire. As Aredian roughly drags Gaius from the cage to the pyre, Arthur demands that he show him some respect. Overcome, Uther has to leave. Meanwhile, Gwen is weaving her way through the crowd, apologising to every person that she pushes aside. Finally she reaches Arthur.
Gwen: Arthur! Arthur! Arthur, you've got to stop this.
Arthur: I can't, Gwen. You know I can't.
Gwen: Merlin has proof that Gaius is innocent.
Arthur: My father's already passed sentence. There's nothing I can do.
Gwen: You can do the right thing, Arthur Pendragon! You can show some faith in a loyal friend, or you can stand by and watch an innocent man die!
Gwen: You did it once before to my father; are you really willing to let it happen again? And you can stop looking at me like that, I know I'm only a servant! I thought you were a prince, so start behaving like one!
Before them, Aredian is about to lower the torch that will set Gaius's pyre alight. At the last moment, Arthur calls a halt to it.
Having gathered everyone together in the throne room, Merlin is sharing the evidence that Aredian's entire campaign has been based on lies. He presents the eyedrops, and the women confirm that they bought the product from the apothecary. In turn, the apothecary states that he was given the eyedrops to sell by Aredian, threatened with execution if he did not. Aredian denies everything, and when Uther gets agitated at Merlin stating that they should search Aredian's chambers, Arthur steps in. He points out to his father that there's no reason not to search Aredian's room.
The guards begin to tear apart Aredian's room as Aredian, Uther, Arthur, Merlin and Morgana watch from the door. One of the guards open the cupboard and an array of amulets tumble out, along with several bottles of belladonna tincture. Aredian denies all knowledge of them. He begins to cough as he accuses Merlin of planting them there. His coughs intensify, and without further warning, a toad falls out of his mouth. Uther is quick to label him a sorcerer, and Aredian grabs Morgana, holding a knife to her throat.
As Uther and Arthur advance with their swords drawn, Merlin whispers an incantation and the knife in Aredian's hand heats up. Yelling with pain, he lets go of Morgana and holds his wrist. Stumbling backwards, he trips over a box and falls backwards out of a window, falling several storeys to his death.
Much later, Uther joins Gaius in his quarters.
Uther: Gaius, I'm glad I found you here.
Gaius: As am I, My Lord. It thought I'd never see these chambers again.
Uther: If anything was damaged in the search, I'll be only too glad to replace it.
Gaius: You're very kind, My Lord.
Uther: Aredian. I can still scarcely believe that he was a sorcerer.
Gaius: Indeed. Is there some reason you wish to see me?
Uther: Yes. I, er...I wanted to say I'm sorry if you suffered at his hands.
Uther: But I was deceived.
Uther: I assure you, Gaius, every measure will be taken to ensure that nothing like this will happen again.
Gaius: I hope that is true, for all our sakes. Now, if you'll excuse me, I have work to do.
Thoroughly outclassed, Uther leaves the room.
Over dinner, Gaius chides Merlin on the rather extreme measures he took to condemn Aredian, and Merlin solemnly swears to never again save his life.