Arthur has set off on a solo mission to prove he is worthy to be King. He is determined to retrieve the legendary Golden Trident from the perilous realm of the Fisher King (Donald Sumpter - Being Human) and return it to Camelot. But Arthur is unaware of the dark forces working within Camelot to bring him down and make sure he never becomes King.
Wicked witch Morgana is one of them and she’s determined to make sure Arthur doesn’t return from his heroic mission. She gives him a bracelet to wear which is supposed to bring him luck but, in reality, it saps his energy, leaving him vulnerable to all sorts of evil.
Merlin knows his master’s life is in danger and is relieved when the force for good that is Gwaine (Eoin Macken) blows back into Camelot and offers to help rescue Arthur...
Source Looks like an episode I would love. But I will be away next weekend. Cannot watch it live.