Birds of my dreams

I had a dream that was like a cool fairytale - mixed up from a book I'm reading and two films I half watched yesterday (Book: set in middle ages about Katherine about Katherine Swynford and John of Gaunt, Movies: Flash Gordon and The Man in the Iron Mask).

Three people were lost in a forest. The hero, the heroine and the wise 'professor' character. They wandered around, it was an old-fashioned futuristic place with crazy trees and plants that had the look of slightly cheap, 70s movie sets. Eventually they came to a huge dome, underneath which it was clearer and lighter than the rest of the forest.

They managed to get inside the dome but almost before they could think about what was happening, some huge birds descended upon them and wrought a strange enchantment...

The trio awoke to find they had been 'rescued' by a group of local people, who took them in and nursed their wounds. It appeared the strangers had been unconscious for several days or weeks even but slowly they recovered and started to integrate themselves with the lives of the kindly people of the dome.

The girl fell in love with the Dome King's son and all was going well until the night of their wedding. That evening, the birds once more descended and the three strangers were told that their enchantment meant they changed into bird people every night after the sun went down.
The three were not aware that this had been happening but all could sense it was true because they had each dreamt strange visions of flying through darkness on swift wings.

The girl was devastated. She knew the king's son would not wish to marry her once he knew of her terrible affliction. And, even if he did, how could she impose her bird-girl heredity upon his future heirs? So she made a bargain.

If the bird people would give her ten years in which to live, love and bear children with the Prince, she would give them her humanity. After the 10 years were up, she would become a fully fledged, full-time bird girl. It was agreed, with one clause - if she had four children who all survived, she would be released from her pledge... the doctor and the hero, meanwhile, would remain on nightly bird duty.

I don't know how it ends