In The Silver Chair, by C.S. Lewis (one of the Chronicles of Narnia), the heroes of the story–two children and one of the Narnian creatures that befriend them–free Rilian, the true Prince of Narnia, from the clutches of the witch, disguised as a Lady in Green.
The true Prince has been in captivity, disguised and bound under the spell of the witch, who pretends to the world that she is his guardian. She at first explains to the children that she must watch him carefully, disguise him in public, and keep him under her constant supervision, because if he were freed he would be incredibly dangerous.
He is disguised in public, and no one can see him as he really is. The Prince that the public is allowed to see resembles a prince, but is not quite right.
That is the result of the witch’s enchantment, which she calls a “cure”. In the single hour each day that her “cure” wears off and he is himself, she claims he becomes insane, and thus he must remain bound.
However, the children, having been sent by Aslan (the Son of the Emperor Over the Sea), to find and rescue Rilian, eventually come upon the Prince in his one hour of freedom from the spell. They find that he is actually not insane, not dangerous, and is the true Prince held captive. Per Aslan’s order, they free him, and momentarily all rejoice.
At that moment, the witch comes in and attempts to bewitch the Prince and the Children that everything they believe about the Prince, and about Aslan, is all wrong. She tries to convince them that their quest is futile, that the truth isn’t the truth, and that they must return the Prince to bondage and be content with the previous arrangement. She nearly succeeds.
Fortunately, their friend the Narnian creature speaks the truth, though it causes him pain, that the Prince should assume his rightful place and that Aslan is indeed real and should be obeyed. It sounds discordant next to the seemingly sweet, yet putrid insinuations of the witch, but awakes the children from stupor and confirms their resolve.
Then the witch reveals herself at last, changing into a massive green serpent who tries to kill them. The Prince, freed from bondage, defeats the serpent in battle. The Narnians and other creatures held under her tyranny are free at last, and live in peace.