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.

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.

A deadly plague spreads through Camelot. When it seems that sorcery can be the only possible explanation, Merlin and Gaius race to find a cure, while Gwen is arrested and sentenced to death for practising witchcraft.

With her sights set firmly on Merlin, Nimueh tricks him into drinking from a poisoned chalice, and he falls dangerously ill. Arthur ventures forth deep into the forest of Balor to find the antidote, but little does he know that he's walking into a trap

Merlin is saved from a terrifying winged beast by a heroic stranger- a young man named Lancelot, who dreams of becoming a Knight of Camelot. In order to thank him, Merlin provides falsified records of Lancelot's noble birth and Lancelot is accepted. However, with the winged beast- discovered to be a Griffin- still on the loose, Merlin's decision could have far-reaching consequences not just for Lancelot but for Camelot...

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.

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.

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.

Uther's past comes back to haunt him as a mysterious Black Knight interrupts Arthur's coming-of-age celebrations, throwing down his gauntlet and challenging the Knights of Camelot to combat. The Black Knight, seemingly unstoppable, makes easy work of his combatants. But who is the Black Knight, and why is Uther so uneasy?

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?

Arthur brings a curse upon Camelot. Eager to help his people, he asks Anhora for advice. But is he brave enough to face the challenges ahead?

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.

On a hunting trip, Arthur comes face to face with a creature of great power from the old religion. When Gaius informs them that it can only be killed by magic, Uther refuses to listen and sends out his knights to kill it. Arthur is fatally wounded and Merlin must go to the Isle of the Blessed to save him. But will he be able to pay the price?

New servant Cedric muscles in on Merlin's position as Arthur's right-hand man, and turns the prince against his loyal friend. Merlin is convinced the slippery newcomer is up to something, and he is right - Cedric is a conman and a thief who is after a magnificent jewel, recently unearthed in a tomb far beneath Camelot. Little does he know, his precious prize is more dangerous than he could possibly imagine. Camelot has never been more vulnerable, but how can Merlin make things right when, thanks to Cedric, he might have lost Arthur's friendship for good? Merlin faces the prospect of turning to the one creature he swore he would never trust again - The Great Dragon.

Arthur is determined to win an upcoming jousting competition at Camelot. Gwen challenges Arthur to give up his spoilt ways after he goes undercover with her and Merlin. Myror shows up at Camelot determined to kill Arthur. Arthur is determined to prove himself and win the contest unaware that he is in danger.

When Morgana's nightmares spill into waking hours, she becomes terrified that she has the power of magic. Gaius is determined to keep her in the dark for her own good but Merlin won't stand by and watch his friend suffer. He knows exactly what she's going through and he knows she needs the truth. Is Merlin about to reveal his secret at last?

Gwen is mistaken for Morgana and kidnapped by the savage outlaw Hengist. Uther refuses to pay her ransom, so Arthur defies his father and heads out into dangerous enemy territory to fight for Gwen's freedom. Merlin suspects Arthur's devotion to Gwen is more than that of a prince to one of his subjects. How will Arthur react when he discovers Gwen is not alone in Hengist's castle? She and Lancelot have found each other again, and powerful feelings rekindle.

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?

Lady Catrina has now been crowned and is now known as Queen Catrina. She accuses Merlin of stealing and he is driven into hiding, and must now find a way to expose her true form.

In his determination to rule magic out of Camelot forever, Uther hires the services of Aredian, a terrifying witch hunter who is most feared due to the fact that he stops at nothing in the quest to uncover all and every kind of sorcery. Even though no one is under direct suspicion, several people in Camelot are afraid that the witch hunter could see straight through them: Morgana is worried that Uther might have her executed and Gaius is concerned for the fate of Merlin and his own, since caring for the young warlock is considered crime and treason. Will all three be able to escape a dreadful fate?

Arthur is challenged to a duel by a mysterious warrior. Arthur and Merlin then find themselves on a quest on Morgause's behalf. A dark secret is discovered by Arthur that could change Camelot forever.

Freya is found by Merlin trapped in a bounty hunter's cage and decides to try and help her escape. Merlin refuses to listen to Gaius' warnings not to get involved. After freeing her Merlin hides Freya in the tunnels beneath Camelot. Merlin is forced to make some hard decisions to keep Freya safe.

Peace talks are held at Camelot when dignitaries from rival kingdoms arrive. King Alined is determined there will be no peace though and will use magic to make sure his wishes happen.

Alvarr is determined to allow magic to be used gain and destroy Camelot. Alvarr needs to reclaim the Crystal of Neahtid to make his plan work. Alvarr and Morgana try to get their hands on the crystal and use a druid boy to help them. Merlin is surprised when he finds out the real power of the crystal.

For the first time in over 300 years the fires of Idirsholas burn and Gaius is worried that a sorcerer has revived the deadly Knights of Medhir. Morgause returns and is determined to end Uther's reign at Camelot.

The Great Dragon is finally free. Full of rage, he attacks Camelot with pitiless intensity. The castle is crumbling and Arthur's men cannot hold out much longer but only a Dragonlord can kill a dragon and Uther wiped them all out years ago. Or did he? Gaius admits one such man could still be alive and in hiding. The last Dragonlord is the key to Merlin's own past as well as the future of Camelot, but will Arthur and Merlin find Balinor in time to save the kingdom?

A year after her disappearance and when almost all hope is lost, Morgana returns to Camelot. While Merlin is afraid she might remember the circumstances of her disappearance and give him away in front of the king, a delighted Uther announces a banquet to celebrate. However, soon afterwards evil magic starts to take hold of the king's mind, putting the safety of Camelot at risk as he is consumed with hallucinations and enemies reach his door. Merlin suspects Morgana is behind the enchantment but his search for the truth puts his life in peril while Arthur is forced to take control and face new foes on his own. Will they succeed to rescue the king and Camelot from destruction?

With the help of the Great Dragon, Merlin manages to return to Camelot only to find out that is it on the verge of invasion: Morgause and Cenred have teamed up and plot against a weakened Uther. Cenred's initial reluctance is won over by the fact that they count on an ally within Camelot walls who will ensure the castle is taken. Uther is unable to rule which forces Arthur to step up front and defend the citadel agains Cenred's powerful army. With the help of Morgause and to make things worse, Morgana plays a deadly card and summons a skeleton army to wreak havoc within the castle walls. Camelot's fate rests once again on Arthur's shoulders and Merlin's magic as they fight in their own way to hold off both an army of the living and an army of the dead. Will they manage to succeed?

When Merlin comes across a secret chamber, he accidentally releases a goblin. The mischievous little creature possesses Gaius, making the wise and renowned court physician turn into a shadow of his former self, quickly developing a taste for gold, ale and magical jokes. To make things worse, the king suddenly becomes bald and a nasty scourge of flatulence hits the royal household. Will Merlin be able to figure out the source of all troubles, return the gobblin back to where he came from and put an end to the havoc before any real damage is done?

Merlin and Arthur find themselves outnumbered in a bar fight but an enigmatic young man helps them win. The man’s name is Gwaine and he risks his own life to protect Arthur but during his act of bravery he is seriously wounded. The Prince decides to take him back to Camelot where he could make a recovery with Gaius' help. Gwaine immediately gets to work: drinking, flirting with the ladies and causing lots of trouble for Merlin who has been instructed to look after him. However, when two unscrupulous knights seem to plot to murder the Prince, will Merlin and Gwaine be able to stop them and save Arthur?

After an unexpected meeting with the enigmatic old sorcerer Taliesin, the wizard takes Merlin to the crystal cave allowing him to witness a glimpse of the future. However, this gesture turns out to be more of a curse than a gift when, much to his horror, Merlin sees Morgana set to kill Uther. The young warlock knows he must do his best to try and stop the future from playing out. But changing the pages of destiny is a very dangerous game and his actions end up having fatal consequences. With the whole of Camelot in a state of grief, will Merlin be able to change the course of destiny and undo the damage he has caused, or will it be 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?

Gwen faces an impossible dilemma when she is forced to choose between saving the life of Elyan, her estranged brother and only sibling or Arthur's, Camelot's prince and the love of her life. When one of them is certain to find death at the hands of Cenred, who will Gwen choose? Once again, loyalty, love and friendships are tested to the limit as Arthur, Merlin and Gwen are forced to put their minds together to try and find a way out of the cruel quandary. Morgana and Morgause, in turn, will do their best ruin their plans. Will good conquer evil or will Gwen end up losing someone she loves again?

Arthur embarks alone on a quest to prove himself worthy of the Camelot throne by retrieving the Golden Trident from the Fisher King. With the Prince beyond the protection of the citadel, Morgana takes the opportunity to use her dark magic. She gives him a precious bracelet that contains a Phoenix Eye, insisting that he wears it at all times for protection. However, the magical jewel takes away Arthur's life force and he is left defenceless in the Fisher King's perilous realm. With the help of Gwaine, will Merlin be able to reach Arthur in time and fulfil his own quest to protect the future king of Camelot?

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

When Uther banishes Gwen from the kingdom, Arthur resolves to leave Camelot with her.

Camelot's legendary tournament only has one rule: there are no rules whatsoever. Terrifying warriors start to fill the mythical city, Gilli between them. Despite his small stature, Gilli is ready to join the action and committed to achieve victory with a secret weapon to help him: magic. When Gilli begins to realise the full extent of his powers, Merlin becomes torn since his new friend is putting his own life in danger as well as threatening the very heart of Camelot with his actions. Will Merlin be able to make Gilli see sense before it's too late?

Arthur and Merlin embark on a dangerous mission to capture the Cup of Life, a powerful magical artifact that carries the gift of immortality. However, before they are able to retrieve the Cup they fall prey to Jarl, an unscrupulous slave trader. They manage to escape when a trusted friend comes to their rescue but with Jarl's help, the Cup of Life ends up in Morgause's hands. Now that the dreadful sisters count on an immortal army at their disposal, will Morgause and Morgana overthrow Uther once and for all?

Will Arthur be able to save Camelot from the evil Morgana? Morgana, newly crowned as Queen of Camelot, begins a reign of terrible evil over the innocent citizens of the kingdom. Counting on Morgause and her immortal army at her command all hope seems lost for Uther, who is forced to witness how his kingdom crumble under the unimaginable cruelty of his own daughter. Meanwhile, on the outskirts of Camelot, Arthur recovers his strength and plans a counter attack with the help of a few loyals at his side: Gwaine, Lancelot, Elyan and Percival. However, Merlin is aware that not even a skilful warrior like Arthur can defeat an immortal foe without magic. Will he be able to reclaim the great sword Excalibur from the Lake of Avalon in time to save the lives of those he cares the most about?

Evil sorceress Morgana summons mighty gatekeeper the Cailleach, who opens a door to another world from which hellish creatures pour forth. As Arthur and his loyal knights take up arms, Merlin discovers the only thing that will stop them is an unimaginable sacrifice.

The kingdom is on the brink of collapse and Morgana poised to strike, in the final part of this opening episode of the fantasy drama. As Lancelot races back to Camelot with the dying Merlin, Arthur must continue on his mission to vanquish the Dorocha without them. Though the Knights know their journey to the Isle of the Blessed is fraught with danger, none could anticipate the sacrifice Arthur intends to make there. Friendship and loyalty are tested to the limit, but in the end, it's the power of love that changes all their lives for ever.

The mighty citadel is buzzing in anticipation of the Prince's birthday celebrations, as the fantasy drama continues. But Arthur's old adversary, Odin, promises to ensure this is one party Camelot will never forget - for among the assembling guests lurks a deadly assassin set to strike. As the dust settles, Camelot is left devastated. Just how far is Merlin prepared to go to put things right; would he really risk everything and reveal his secret?

A mysterious visitor arrives in Camelot seeking a very special prize: a dragon's egg.

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.

Merlin becomes a deadly weapon in Morgana's fight for supremacy when he falls into her hands. By recurring to ancient magic, she manages to turn friend against friend and creates the perfect assassin out of the young sorcerer which puts an oblivious King Arthur in great danger. Will anyone notice Merlin's unusual behaviour before he is able to do any serious harm to the King?

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?

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?

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?

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?

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.

Morgana is now the head of a vast Southron army and a deadly net is closing around Camelot. After the sorceress strikes everyone is forced to run for their lives including Arthur. It is down to Merlin to try and save Arthur from Morgana's clutches.

Morgana and Helios have successfully captured Camelot, and Merlin and Arthur are outlaws on the run, in the last episode in this season of Merlin. Trapped in Ealdor with a ruthless army closing in, their situation becomes desperate. Arthur must take control before Camelot is lost forever… But faced with Agravaine’s betrayal and the strength of Morgana’s force, the young King has lost his conviction. Only Merlin can restore his faith, and only an extraordinary act can prove to the King that he was born to rule. Will the young warlock convince Arthur before his dreams of Albion fall to pieces?

Camelot faces a new golden age, but even as the city flowers, the dark seeds of destruction are being sown. In the frozen wastelands of the north, men are disappearing without a trace. King Arthur and his knights undertake a dangerous mission into the unknown in search of answers - but once there, Merlin finds himself locked in a battle unlike any he has fought before.

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.

When a stranger gives Arthur the power to summon the dead, the king finds himself torn between head and heart. Unable to resist temptation, he seizes the chance to speak to the person he misses most – his father, Uther Pendragon. But the spirit world is a dark and dangerous place, for little does Arthur realize that his decision comes at a terrible price. Against all odds, Merlin must put right Arthur's mistake before Camelot, and everything they have built, is destroyed forever.

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?

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 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?

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 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.

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?

Mordred finds himself torn between loyalty and love, but little does he realise that the path he chooses will shape Camelot's destiny. As the drums of war beat ever louder, a desperate Merlin feels trapped by the cruel circle of fate - is he powerless to stop his dreams of Albion from crumbling to dust?

High in the mountains, a great horde gathers; Morgana prepares for war with a vengeful Mordred at her side. Merlin feels the weight of his destiny like never before as the ancient prophecies play out with terrifying accuracy. But before he can save his beloved Camelot, he must save himself. For it is not just the kingdom Morgana wishes to destroy – it is also Emrys.

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?