S4·E10 A Herald of the New Age

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?