There are moments in some Fairy Tales when the protagonist falls asleep and dreams an important solution or missing piece that helps them along.
This image is inspired by a fairy tale called Jorinda and Joringel. It can be found in the Brother's Grimm collection of stories. You can read a version here.
In the middle of the story Joringel dreams of a blood-red flower with a pearl inside it that can dissolve any enchantment. This is handy because his beloved is currently in the shape of a songbird, locked up in a witch's castle.
Oh, but how to tell a dream pictorially? I chose to go with the red colour for all the dream bits. It's hard in fairy tales where so many peculiar things happen, to emphasise the dream part.
I love this retelling of Jorinde and Joringel by Gypsy Thornton. It's a steampunk mash-up called Cages. You can read or listen to it here.