They keep their secret in a parade of clouds, playing hide and seek.
16 seconds sound clip from the The Last Unicorn movie soundboard.
You can hear this line at 00:57:06.879 in the Blu-ray version of the movie.
Quote context
[...]
- Do they know where do unicorns go? Where winged horses fly?
- North Wales lost at sea and never seen again.
- Go, go and ask the magpie, 'Where do unicorns go?'
- In the trees, the birds have learned to speak every color.
- They keep their secret in a parade of clouds, playing hide and seek.
- Do they know where do unicorns go? Where winged horses fly? (2)
- North Wales lost at sea and never seen again. (2)
- Does myth and mystery lie where the unicorns go?
[...]