Only the miraculous arrival of Arthur, heir to the Pendragon dynasty, allows Guenevere to claim her mother's throne.

Smitten by the bold, sensuous princess, Arthur offers to marry her and unite their territories, while still allowing her to rule in her own right.

Arthur's glorious rule begins to crumble, however, when he is reunited with his mother and his long-lost half-sisters, Morgause and Morgan.

Before Arthur's birth, his father - the savage and unscrupulous King Uther - banished his wife's young daughters, selling Morgause into a cruel marriage and imprisoning Morgan in a far-off convent.

Both daughters have reason to avenge their suffering, but only one will strike the deadliest blows against the King and Queen, using her evil enchantments to destroy all Guenevere holds dear.