Last week's episode saw Merlin and Arthur escape from the clutches of the druids and sneak into Morgana's castle.
In Camelot, Gwen refused to reconsider Sefa's death sentence, hoping to capture her father Ruadan if he tried to save his daughter. Ruadan did just as Gewn had planned and rescued Sefa from her cell - but he was fatally wounded in the process and later died in the forest surrounding Camelot.
Meanwhile, as Morgana was poised to kill Arthur, Mordred changed his allegiance, saving Arthur and leaving Morgana mortally wounded.
This episode, with Ruadan dead, Morgana injured and Mordred the newest knight of Camelot, Arthur faces a new enemy, with a familiar face... A stranger gives the young King the power to summon the dead, and soon enough Uther is back. By the looks of these pictures and video clip, the next episode will be a spooky one...