This season presents a major turning point in the story. The first few seasons were mostly a hodgepodge of adventures with young Merlin and his friend Arthur, but the fourth season was a sort-of end-of-innocence tale, as the characters dealt with the death of Uther, the betrayal of Morgana, and Arthur's ascent to the throne. The season ended with Arthur's first act of true rebelion against the status quo of the kingdom, when he married his love, Gwen, despite her lower class status.

BBC One has released a trailer for the upcoming fifth season of its hit fantasy drama, Merlin.