Uther is determined to once and for get rid of all the magic being performed inside Camelot. Aredian, a witch finder is called to Camelot to help deal with the problem. Gaius tries to make Merlin see how much danger he is in. Morgana is certain that Aredian will discover her secret and Merlin attempts to protect bother her and Gaius.
The Great Dragon attacks Camelot after finally being free. Arthur’s men find themselves fighting a loosing battle. A Dragonlord is needed to kill the dragon and Gaius admits one could still be alive. Arthur and Merlin attempt to find Balinor to save Camelot and his enemy Uther.
For the first time in over 300 the fires of Idirsholas burn years and Gaius is worried that a sorcerer has revived the deadly Knights of Medhir. Morgause returns and is determined to end Uther’s reign at Camelot.
Alvarr is determined to allow magic to be used gain and destroy Camelot. Alvarr needs to reclaim the Crystal of Neahtid to make his plan work. Alvarr and Morgana try to get their hands on the crystal and use a druid boy to help them. Merlin is surprised when he finds out the real power of the crystal.
Peace talks are held at Camelot when dignitaries from rival kingdoms arrive. King Alined is determined there will be no peace though and will use magic to make sure his wishes happen.
Freya is found by Merlin trapped in a bounty hunter’s cage and decides to try and help her escape. Merlin refuses to listen to Gaius’ warnings not to get involved. After freeing her Merlin hides Freya in the tunnels beneath Camelot. Merlin is forced to make some hard decisions to keep Freya safe.
Arthur is challenged to a dual by a mysterious warrior. Arthur and Merlin then find themselves on a quest on Morgause’s behalf. A dark secret is discovered by Arthur that could change Camelot forever.
Queen Catrina settles into her new role at Camelot and her influence over Uther increases. Merlin is forced to go Merlin tries to expose Catrina without being caught and break her hold over the kingdom.
Merlin and Gaius suspect that Lady Carina is not quite as she seems after showing up in Camelot.Arthur isn’t happy when his father flirts with her. When Merlin discovers that she is really a troll he finds it impossible to get Arthur to listen to him. Merlin tries to stop Catrina from ruining Uther’s life but she has her eyes set on an even bigger prize.
After Gwen is mistaken for Morgana she is kidnapped by Hengist. Arthur attempts to rescue her and Merlin thinks that Arthur cares about her. Arthur discovers Lancelot has already shown up when he tries to rescue her.