Ep 5. His Father's Son

In the fifth episode of Merlin season 4, titled "His Father's Son," the main focus of the story is on Mordred. The episode begins with him being attacked by a group of bandits while he is on his way to visit Morgana. Mordred manages to handle the situation with his excellent fighting skills, and subsequently arrives at Morgana's hideout.

Arthur, Merlin, and their knights are out on a ride, as is their usual practice. They soon come across a group of Camelot soldiers who are brutally murdered by someone. Arthur and his knights realize that the killer is still in the vicinity and decide to investigate. They learn that the attacker is Mordred, but as they do not know him, they let him go.

Mordred confides in Morgana about how he feels isolated from both the druids and Arthur. Morgana realizes that Mordred is Arthur's illegitimate son who was born to one of Arthur's previous female acquaintances. Morgana persuades Mordred to consider joining forces with her against Camelot.

Meanwhile, Merlin has a vision of Mordred killing Arthur in the future, and he becomes obsessed with stopping it from happening. Arthur and his knights come across Mordred once again, but this time there is a confrontation, during which Mordred inadvertently saves Arthur's life.

This incident changes Arthur's opinion of Mordred, who is then invited to join the knights of Camelot. Merlin, on the other hand, remains wary of Mordred's intentions. In a private conversation between Morgana and Mordred, Morgana convinces Mordred to remain loyal to her cause and to befriend Arthur as a way of gaining his trust.

Despite Merlin's reservations, Mordred gains acceptance from the knights, who admire his agility and fighting prowess. The episode ends with Merlin once again having a prophetic vision of Mordred killing Arthur.

Overall, "His Father’s Son" is an intriguing episode that sheds light on Mordred's character and his relationship with Arthur and Morgana. The episode effectively portrays Mordred as a sympathetic character who is struggling with his identity and finding his place in the world, while also emphasizing the underlying tensions between Camelot and the druids. With its engaging storyline and strong performances by the cast, this episode of Merlin is an excellent addition to the show's fourth season.