Uther's past comes back to haunt him when a mysterious Black Knight rides into Camelot. The visitor quickly makes his presence felt, throwing down his gauntlet and challenging the Knights of Camelot to mortal combat.

As the formidable fighter picks off his opponents one by one, it becomes clear he cannot be beaten; is it just his superior skill, or is there something more sinister behind his invincibility? With Arthur set to face this deadly foe, will Uther overcome his pride and do the right thing, or is the truth too difficult to face?

When Arthur kills a unicorn, the most prized and mystical of creatures, Merlin's heart is filled with foreboding.

The young sorcerer's concerns are soon validated when a curse descends on Camelot. With the fabled city fast running out of both food and water, Arthur is desperate to help his people. But to do so he must listen to the mysterious Anhora and he doesn't like what he hears. Will Arthur take Anhora seriously before it's too late? And if so, is he brave enough to face the challenges that are thrown at him?