The Game is a children's fantasy novel written by Diana Wynne Jones.

[2][3][4] It explores a young girl's life and her relation to the "Mythosphere."

Grandad is overworked and travels a lot; Grandma is much too strict and never lets her meet any children her own age.

To Hayley's shock, the number of people in her family is much larger than she thought; to her delight, the children all play what they call “the game,” where they visit a place called “the mythosphere.” And while she plays the game, Hayley learns more about her own place in the world than she had ever expected.

Hayley encounters various mythological figures during the course of her adventures in the mythosphere, including Actaeon and Baba Yaga.