A mysterious illness draws Merlin to a distant village. But it soon becomes clear that there is more at stake than just his patients' well-being as something sinister turns the air sour. Far from home and with no-one to trust, Merlin becomes embroiled in a deadly game of cat and mouse. No longer sure who is the hunter and who is the hunted, can the young warlock survive long enough to uncover the truth?

And so it seems the Prophets did not lie. As the great battle rages on Camlann's mighty plain, Merlin faces his moment of destiny. Can he find the strength to save the man he made a King; the Camelot they fought to build; and the brotherhood they shared?

Merlin is told by the Great Dragon that it is his destiny to make sure that the young Prince Arthur is kept safe. Anybody caught performing magic is punished with death and Merlin is not a fan of Arthur. When Arthur's life is endangered Merlin finds himself tested.

Morgana ends up discovering a powerful ally in the Southron warlord Helios and they come up with the perfect plan to bring Camelot to its knees. With Arthur preoccupied by the beautiful Princess Mithian, it ends up falling to an absent friend to raise the alarm.

Darkness steals into the very heart of Camelot, as Morgana and her puppet Queen hatch a sinister plan to murder the King. But when stable hand Tyr Seward becomes caught in the crossfire, he threatens to ruin everything… As the plot thickens and reaches its deadly climax, can a suspicious Merlin unravel the truth before it’s too late?

When the Lady Morgana is struck down with a mysterious illness, Gaius is at a loss for a cure. Thankfully a new physician, Edwin Muirden is on hand to bring the King's ward back from the brink.

With Princess Mithian as the perfect bait, Morgana conjures a deception so powerful that the whole of Camelot is taken in - even Merlin himself. But as the storm clouds gather, will the young warlock see through the lies? Or will Morgana at long last fulfil her dreams of revenge?

When Gwen is snatched from Camelot without warning, Merlin knows there can be only one person responsible: Morgana. Arthur is determined to rescue his Queen – but it's not going to be easy, for she is locked in the Dark Tower, a place that haunts the dreams of men. Arthur and his Knights must embark on a quest like no other, battling through a landscape riddled with hidden dangers, perilous obstacles and magical beings. As they near their goal, Merlin's sense of dread reaches breaking point. What twisted game is Morgana playing? And more importantly, just what is the final test that awaits them in the tower?

Morgana leads a terrifying manhunt in pursuit of her old foe Alator of the Catha, for she knows without doubt that he can tell her exactly where to find Emrys. Merlin's life is in severe danger, so when the mysterious Finna offers to help him, is he right to trust her?

Morgana has a nightmare and sees Arthur's death at the hands of a strange but beautiful girl. Meanwhile, hunting in the forest, Merlin and Arthur save the same girl, Sophia, and her father, Aulfric from attack by bandits and bring them to Camelot for refuge. Morgana realizes that Sophia is the girl from her nightmare and tries to warn Arthur, who is smitten with her. As the truth of Morgana's magical gift for seeing future events unfolds, so does a father and daughter's plan to bring down the kingdom of Camelot by sacrificing Arthur in return for eternal life.

Gwen's father, Tom, helps a sorcerer named Tauren turn lead into gold using a magic stone. As Tauren escapes, Tom is caught and will await trial. Whilst looking for Gwen, Morgana finds the magic stone, and Merlin can sense it. When Tom is killed by Uther, Morgana is out for revenge on Uther.

Morgana joins forces with enigmatic wizard Alator to uncover a secret that could change the course of destiny, as the magical drama continues. With allies on both sides of the castle walls, can anyone stop her before Merlin's greatest secret is revealed?

When Sir Lancelot returns from the dead, old feelings reignite, as the drama continues. Gwen must fight temptation before she commits an unspeakable act of betrayal; one that would destroy the legacy of Camelot forever. With heads and hearts thrown into turmoil, Merlin becomes suspicious. Can a man really defy death, or is there something more sinister at play?

As dawn breaks across the icy tundra, Merlin and Arthur are close to exhaustion. With each tortured step, the fortress of Ismere looms ever nearer and Merlin's fear intensifies. What game is Mordred playing? And what powerful secrets are Morgana and the druid Ruadan (Liam Cunningham) searching for amongst its twisted catacombs? It seems like this time, not even Merlin can stop Arthur from walking right into the lion's den… For in this bleak and transient wilderness, only one thing is certain: the great trial for Albion has finally begun.

In the inky depths of an ancient pool, three soothsayers cast a dark judgment upon the King of Camelot. But despite Merlin’s warnings, headstrong Arthur refuses to take the words of the Disir seriously and their fury rains down on Camelot. Only the greatest sacrifice can appease them, and with the kingdom in jeopardy, is it one that Arthur is prepared to make? Faced with the King’s uncertainty, Merlin has just one chance to save him from his destiny, but this decision comes at the highest price.

When Merlin agrees to help a young Druid boy, he has no choice but to leave Camelot on a dangerous mission. And with the citadel distracted by the visit of the fearsome Sarrum of Amata, it seems that no one will notice his absence. But as the sky darkens, so do Merlin's suspicions - is there more to Daegal than meets the eye? And can a man as ruthless as the Sarrum ever really be trusted? Too late, the young warlock realises he's made a terrible mistake.

Merlin knows he must act fast before Morgana’s twisted control over Gwen gets further out of hand. But only the most powerful magic can save the Queen and this will not be easy, even for Merlin. As the High Priestess tightens her grip on Camelot, one thing is clear - she will not give up her puppet without a fight.

Merlin is stunned when his mother, Hunith, turns up in Camelot--bruised, battered and desperate for help from Uther. She explains to Uther that a bandit named Kanen and his men have been attacking her village demanding all of their harvest or he will kill them. When Uther refuses to help, Merlin leaves Camelot to protect his mother and friends. To Merlin's surprise, Arthur, Morgana and Gwen join forces with him to save his village--but at what cost?

An old flame of Gaius' arrives in Camelot under the influence of a Manticore.

Arthur faces his first true test as King when he incurs the wrath of the formidable Queen Annis. With the lives of thousands hanging in the balance, Arthur must find the strength to be his own man and become the leader Camelot so desperately needs.

The Camelot Knights stumble across an eerie shrine deep in the forest, its chilling atmosphere betraying a dark history best left undisturbed, as the magical drama continues. But when Elyan ignores Merlin's warning, his actions spark a chain of events more frightening than anyone could possibly have imagined... Can a grievous wrong be put right? Or will past demons change the future forever?

Camelot is hosting its annual sword tournament and knights from throughout the realm have come to compete for its coveted title. Amongst those hoping to win the crown is Knight Valiant.

Merlin finds himself becoming friends with Morgana when he helps a boy stay hidden. The two of them try to get the boy back whence he came, but things turn bad when Uther announces that anyone helping the boy will be executed.

Lady Catrina and her strange servant Jonas arrive in Camelot, where they are welcome to stay by a most delighted king Uther, who becomes captivated by his latest guest. Arthur, on the contrary, far from sharing his father's enthusiasm and in the sight of the flirting going on, is pretty appalled with the situation. Merlin and Gaius have the feeling that she is not what she seems and their suspicions are proven true when Merlin discovers that Lady Catrina is a troll and that unfortunately, her intentions are far beyond the prize of a king's heart. Horrified, he reveals the truth to Arthur, who doesn't believe him. Merlin embarks in the task of proving the real nature of the woman while at the same time saving Uther from ruin and Camelot from fall. Will the young warlock be able to overcome the powerful magic of the troll before it's too late?

Uther pressures Arthur into an arranged marriage with a visiting princess, Elena, though Merlin soon has reservations after discovering that Elena may not exactly be who she claims to be. As he tries to uncover the princess' dark secret, he learns that Elena's nanny is a Pixie. But what are their motivations? Who do they work for? And most important of all, what benefit do they get from her marriage to Arthur, the heir to the throne of Camelot? Will Merlin be able to get to the bottom of it all and prevent Arthur from making the biggest mistake of his life?