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. (TV Guide UK)

Arthur and Merlin are exhausted as they make their way across the icy plains toward the fortress of Ismere, but with each tired step, the warlock's fear intensifies. What powerful secrets are Morgana and the druid Ruadan searching for among its twisted catacombs? And what dangerous game is Mordred playing? It seems not even Merlin can stop his king from walking into certain danger as the great battle for Albion begins. (TV Guide UK)

A stranger gives Arthur the power to summon the dead, so he seizes the chance to speak to the person he misses most - his father, Uther Pendragon. But the young king's decision comes at a terrible price, for the spirit world is a dangerous place, leaving Merlin fighting against the odds to put right the mistake before Camelot is destroyed. (TV Guide UK)

Morgana makes a sinister pact with Nemeth and King Odin, using Princess Mithian as bait to lure Arthur to his death - a deception so powerful that the whole of Camelot, even Merlin, is taken in. Can the young warlock see through the lies before it is too late? (TV Guide UK)

In the inky depths of an ancient pool, a trio of soothsayers cast a dark judgement upon Arthur. But despite Merlin's warnings, the headstrong king refuses to take their words seriously, so their fury rains down on Camelot. With the kingdom in jeopardy, only the greatest sacrifice can appease them -- but is it one Arthur is prepared to make? (TV Guide UK)

Gwen becomes the traditional damsel in distress when she is snatched from Camelot and locked in a dark tower, so Arthur mounts his trusty steed and sets out to rescue his bride, accompanied by Merlin and his loyal knights. However, her kidnapper is none other than Morgana, who has imprisoned the queen in a place that haunts the dreams of men. Before them lays a landscape riddled with hidden dangers, perilous obstacles and magical beings -- but surely, the sorceress wouldn't have made it quite that easy? (TV Guide UK)

Morgana finds herself in a unique position of power, having a Camelot insider under her spell -- and now the pair hatch a plot to murder the king. But when stable hand Tyr Seward becomes caught in the crossfire, he threatens to ruin everything. Can a suspicious Merlin unravel the truth before it is too late? (TV Guide UK)

The warlock agrees to help a young druid boy, Daegal, although to do so he has to leave Camelot on a dangerous mission -- just as the citadel is playing host to the fearsome Sarrum of Amata. He hopes 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 Sartre be trusted? (TV Guide UK)

The warlock is determined to break Morgana's twisted control over Gwen. But it will be no easy task, even for Merlin, as only the most powerful magic can save the Queen -- and the high priestess will not give up her puppet without a fight. (TV Guide UK)

Morgana is desperate to find the warlock's alter-ego Emrys, and seeks help from an old foe, the powerful wizard Alator. Merlin's life has never been in more danger, so when the mysterious Finna offers to help him, is he right to trust her? (TV Guide UK)

Mordred becomes torn between loyalty and love, little realising the path he chooses will shape Camelot's destiny -- and as the drums of war beat louder, Merlin feels trapped by the cruel circle of fate. Can he really do nothing to stop his dreams of Albion crumbling to dust? (TV Guide UK)

Morgana prepares to wage war on Camelot with Mordred at her side, while Merlin finds the burden of his destiny weighing heavily as the ancient prophecies play out with unnerving accuracy. It soon becomes clear that the young wizard must find a way to save himself before he can help his allies bring about the salvation of his beloved kingdom. (TV Guide UK)

As a fierce battle rages on Camlann's mighty plain, just as the prophecies foresaw, Merlin must find the strength to overcome his greatest challenge yet as he seeks a way to protect Camelot. As he fights to save the kingdom from the attacking hordes and keep Arthur safe from harm, the young wizard finally comes face to face with his destiny. (TV Guide UK)