She is a princess who is doomed to become a swan by day, holding her human form by night. The man the Princess loves is also beloved by a beautiful, but wicked witch who has wreaked her rage and jealosy upon her unfortunate rival.
Only the kiss of true love upon the beak of a swan will break the spell -- but who could fall in love with a swan? And who would kiss a swan upon its beak? Hmmmmm . . . .
It is fortunate that nearly every fairytale I've ever read ends with the words, "and they lived happily ever after."