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. (TV Guide UK)
With the Kingdom on the brink of collapse and Morgana poised to strike, Arthur continues on his mission to the Isle of the Blessed. But with Lancelot racing back to the castle with the dying Merlin, there is no one to stop the prince making the ultimate sacrifice to save his precious Camelot. (TV Guide UK)
Camelot is buzzing in anticipation of Arthur's birthday celebrations, but the prince's old adversary Odin is determined this is a party the people will never forget, for among the carnival performers is an assassin ready to strike. When the hired killer makes his move, Merlin is left in an impossible dilemma -- to put things right he would have to reveal the secret of his magic. (TV Guide UK)
A mysterious stranger arrives in Camelot claiming to have located the final part of a key to a tomb containing the last remaining dragon's egg. Merlin is intrigued and promises to help him -- but the man's motives are soon called into question. (TV Guide UK)
Arthur faces his first true test as king when he incurs the wrath of the formidable Queen Annis -- and as thousands of lives hang in the balance, he struggles to find the strength to become the leader his people so desperately need. (TV Guide UK)
Morgana uses ancient magic to bend Merlin to her will, turning him into a deadly assassin on a mission to kill the king. But with Arthur oblivious to the danger, his only hope rests with someone else noticing his manservant's strange behaviour before he commits the evil deed. (TV Guide UK)
Morgana sets out to uncover Merlin's secret, an act that would change the course of destiny - and to ensure success, she joins forces with enigmatic wizard Alator, meaning the young warlock is more reliant on his friends and allies than ever before. (TV Guide UK)
The young warlock is struck by a mysterious illness that draws him to a distant village where something sinister lurks. Before long, he finds himself embroiled in a deadly game of cat and mouse -- but he cannot be sure if he is the hunter or the prey. (TV Guide UK)
Lancelot's return from the dead reignites old feelings for Gwen, forcing her into temptation -- a contest that, if she loses, could lead her to commit an unspeakable act of betrayal that would destroy the legacy of Camelot for ever. But Merlin is suspicious about the knight's reappearance and believes something more sinister is at play. (TV Guide UK)
The knights discover an eerie shrine deep in the forest, which Merlin tells them is best left undisturbed. But the warlock's warnings go unheeded by Sir Elyan, whose careless actions spark a chain of events more terrifying than anyone could possibly have imagined. (TV Guide UK)
Morgana finds an ally in powerful warlord Helios and they plot to take over Camelot. However, Arthur and his people are so preoccupied with a visit from the beautiful Princess Mithian, it is left to the returning Gwen to raise the alarm -- and her appearance soon reopens old wounds. (TV Guide UK)
Morgana and her massive army close in around Camelot, and when she strikes, the ferocity of her attack forces everyone to run for their lives -- even Arthur. But the sorceress will not let him escape that easily -- and so begins a chilling hunt for the king. Can Merlin save his master's life yet again? (TV Guide UK)
Morgana and Helios have captured Camelot, leaving Arthur and Merlin on the run -- and faced with the betrayal of a trusted courtier and the strength of the enemy, the king has lost the will to fight. It seems only the young servant can restore his master's faith -- but only an extraordinary act can prove he was born to rule. (TV Guide UK)
