A fiercely funny picture book from author Douglas Rees and illustrator Isabel Muñoz about the fantastic friendship between a little girl and a creature out of legend.When Willa Cathcart Wilmerding, the bravest girl in the world, is told she must stop her nightly tradition of howling at the moon, she decides to run away. High in the mountains, she meets Buttercup the Bigfoot, a friend unlike any other!Willa and Buttercup do everything together. They leap up and down the mountains, soar over mighty crevasses, and make each other crowns of flowers—but their favorite thing to do is climb a high peak and HOWL at the moon.This playful story of friendship, freedom, and ferocity will have picture book readers eager for a Bigfoot friend of their very own.