When Arthur kills a unicorn while out hunting, the knights applaud him for his efforts. As Merlin rushes to the animal’s aid, he sees an old man watching through the trees, who quickly disappears. The next morning, Arthur and Uther find that crops have died all over the kingdom and when all the water in Camelot’s well turns to sand, Gaius suggests that a curse has come to Camelot.

That night, Merlin and Arthur are on patrol when they come across a mysterious stranger – the same old man Merlin saw in the forest – who introduces himself as Anhora, the keeper of the unicorns. Anhora tells them that Arthur unleashed the curse threatening Camelot when he killed the unicorn. But Arthur is angry at the suggestion that he’s to blame for the crisis.

Before the man disappears again, Anhora tells Arthur that he will be tested and, until he has made amends for his actions, Camelot will be damned. Can Arthur rid the Kingdom of this dreaded curse?