<Tr> <Td_colspan="7"> Morgana succeeds in stripping Merlin of his magic and he is helpless to aid Arthur who has decided to meet Morgana's forces at Camlann . To regain his magic Merlin travels to the Crystal Cave in the Valley of the Fallen Kings . Using a spy, Morgana tracks and entombs Merlin in the Cave . Awakened by a vision of his father, Merlin's magic is restored and he warns Arthur of Morgana's battle plans while the King sleeps . The battle commences and Merlin emerges from the Cave as Emrys . </Td> </Tr> <Tr> <Th> 65 </Th> <Td> 13 </Td> <Td> "The Diamond of the Day - Part 2" </Td> <Td> Justin Molotnikov </Td> <Td> Julian Jones </Td> <Td> 24 December 2012 (2012 - 12 - 24) </Td> <Td> 7.80 </Td> </Tr> <Tr> <Td_colspan="7"> Emrys arrives at Camlann, and uses his magic to knock Morgana unconscious, order Aithusa to leave, and strike down many of Morgana's men . The battle culminates in Mordred dealing Arthur a fatal wound, only to receive one in return . While tending to Arthur, Merlin confesses that he is a sorcerer . Arthur's only chance of survival is the powers of the Sidhe of Avalon, so Merlin sets out to reach the lake . In Camelot, Morgana's spy is discovered and hanged, leading Gwaine, along with Percival, to hunt down Morgana . However, she overpowers them and magically tortures Gwaine into confessing Arthur's whereabouts; Gwaine passes out shortly afterwards in Percival's arms . Morgana catches up with Merlin and Arthur and drives their horses away, but she is killed by Merlin wielding Excalibur . Without horses, Merlin cannot get Arthur to the Isle in time, and the King of Camelot dies in Merlin's arms, after thanking his friend for everything he has done . Merlin beseeches the Great Dragon to carry Arthur's body to the Isle, and the Dragon does so . As Merlin desperately tries to drag Arthur's body to the lake, the Great Dragon tells Merlin he has succeeded, and that as the Once and Future King, Arthur will rise again in Albion's greatest hour of need . As the Dragon departs, Merlin flings Excalibur into the waters of Avalon and sends Arthur's body after it . Guinevere ascends the throne of Camelot . In the present day, it seems an immortal Merlin still waits for the Once and Future King to rise again . </Td> </Tr>

When does arthur find out that merlin is a wizard
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