As Morgana and Gwen leave Camelot on a pilgrimage to Morgana's father's grave, they are ambushed in the forest by outlaws. Morgana and Gwen try to flee but are met by lead outlaw, Kendrick; who proclaims that Morgana is more valuable to him alive.
As Morgana and Gwen put an escape plan into action at the outlaws' camp, Arthur is ordered by Uther to find Morgana once they haven't heard back from the travelling party. In the forest, Morgana and Gwen attack Kendrick and flee. They are chased through the forest until Gwen is injured and urges Morgana to run on and find help. Morgana, scared, runs on as Gwen defends herself by killing one of the outlaws.
Arthur and his men come by the scene of the original ambush and check for any survivors. Merlin finds a ransom note left by Kendrick, and Arthur leads his men through the forest following a trail. Armed with his crossbow, Arthur almost shoots upon hearing a noise; but is instead met by Morgana. He asks where Gwen is, to which Morgana can only respond by shaking her head tearfully.
At the outlaws camp, Gwen is given Morgana's robes to wear as the outlaw Hengist (who perpetrated Morgana's abduction) has never seen Morgana before, therefore Gwen is to assume her identity. Morgana, meanwhile is returned to Camelot and a relieved Uther, who refuses to send a rescue party out for Gwen once he realises Hengist is behind the abduction. Morgana begs Arthur - who tries to hide his reaction to the possibility that Gwen has died - to do something to save her, but he admits there is nothing he can do.
Gwen is taken to a savage village where she is met by Hengist. Hengist marvels over Gwen's beauty as she demands to be released, however, she is imprisoned in the dungeons. In the castle, Morgana chastises Arthur until she realises that Arthur is packing to go and rescue Gwen. Gaius wishes Merlin a safe journey and the two set off out of Camelot. As Gwen is forced to eat with Hengist and his people, she is subjected to watch a bout of cage fighting; where she is reunited with Lancelot, who is a competitor. Lancelot wins the fight but does not kill his opponent after seeing Gwen. Lancelot's opponent is then killed by a ferocious creature.
Meanwhile, Arthur grows impatient as Merlin seems to be slowing their trip down; stating that they do not have time to waste as Gwen's life is at stake. In the dungeon, Gwen communicates with Lancelot through a grate in the wall. Gwen reiterates to Lancelot the story of how she got there and how she fears she will meet the same fate as the fighter in the cage, but Lancelot reassures her he will not let that happen. Lancelot reveals he has been earning a living fighting for entertainment as he hasn't had many opportunities to lead a noble life since they last met in Camelot. They share a tender moment as Lancelot reveals he has thought of Gwen often.
In the forest, Arthur says he couldn't sleep because he is so worried about Gwen. Merlin states he hasn't seen Arthur like this over anybody before but Arthur attempts to divert the conversation. Hengist becomes suspicious after he has not heard back from Uther with a response to the ransom, and threatens Gwen with her death if he does not hear from Uther by dawn. Arthur and Merlin try to figure out the best way to get to Gwen, by passing through the tunnels of Andor; which are infested with Wildren, giant human eating rats. Lancelot secretly visits Gwen and tells her he will not let her die and Gwen admits her feelings for him, giving him a reason to live. He states that he will return by nightfall.
As Arthur and Merlin wash the berries used to deter the Wildren off their faces, Arthur apologises for risking Merlin's life. Merlin challenges Arthur to admit his obvious feelings for Gwen, to which a frustrated Arthur states that he can't admit he thinks about her constantly, that he cares for her more than anyone and that he doesn't know what he'd do if she is harmed because there is no opportunity for them to be together. By admitting his feelings for Gwen, knowing that he cannot bring their relationship to fruition, hurts Arthur too much. When asked why nothing can happen, Arthur simply states that his father wouldn't even consider sending a rescue party out for a servant, much less allow Arthur to marry one. Saddened, Arthur laments to Merlin that what he and Gwen have can only ever be all talk; to which Merlin says with conviction that Arthur can change the class standards when he is king. Arthur dejectedly states that he can't expect Gwen to wait for him, but Merlin says she will because she feels the same way for him. Merlin reassures Arthur that Gwen is still alive and the two set off after Arthur makes Merlin promise not say anything about his feelings for Gwen.
Meanwhile, Hengist grows evermore suspicious of the lack of contact between Uther and the kidnapped 'Morgana'. Kendrick is killed when confronted by Hengist about his deceit. Lancelot, having successfully sedated Hengist's men, rescues Gwen and they escape the dungeons. Hengist arrives to find Gwen's cell empty and they pursue Gwen and Lancelot. Gwen refuses to leave Lancelot as he prepares to fight for her. They share a kiss and Gwen promises that her feelings for Lancelot will not fade as she runs through the tunnels. Lancelot faces Hengist's men and he is put back into the fighters' cage. Lancelot is promised pain by Hengist, however Lancelot proclaims his love for Gwen. As the door to the cage is opened, Gwen is brought in and trapped with him.
On the outer of the castle, Arthur and Merlin scale the walls. As they make their way inside, Merlin distracts Hengist's men as Arthur knocks them out. They disguise themselves as Hengist's men and continue looking for Gwen. In the cage, Gwen and Lancelot are sentenced to death. The Wildren is released into the cage just as Arthur and Merlin enter the room. Arthur jumps into the cage and he and Lancelot fight the Wildren together. As they fight, Arthur learns Lancelot is there to save Gwen as well; and they escape through the tunnel. Lancelot offers to stay back to fight and Merlin uses magic to lock Hengist in with the Wildren.
As they escape the tunnel, Gwen realises that Arthur has come without his knights and as she is helped up by Lancelot they share a meaningful glance; upsetting Arthur and surprising Merlin. Lancelot thanks Arthur for saving them as they leave. In the forest, Arthur and Gwen share tense glances as Lancelot points out the bravery of Arthur and Merlin risking their lives. Arthur points out that he defied his father in order to save Gwen, only through the begging of Morgana and as Gwen looks offended, she announces she is going to get rest. Arthur, looking even more upset follows suit and suggests everyone does the same. Lancelot offers to stand guard and Merlin joins him.
Lancelot asks Merlin about Arthur's true agenda for rescuing Gwen and comes to the conclusion he too has feelings for her. Merlin asks Lancelot if he feels the same towards Gwen, to which he responds that he does but they don't matter as he will not come between Arthur and Gwen. He asks Merlin to tell Gwen that she has changed him forever and that some things cannot be. As Gwen wakes, Merlin reluctantly tells her Lancelot has gone and passes on his message. Arthur notices how affected Gwen is by the news but does not say anything, merely stating they should continue home, leaving her in tears. The trio return to Camelot where Morgana waits for them. Morgana and Gwen happily embrace as Arthur shoots Gwen a rather heartbroken glance before leaving.