A poignant and unforgettable story about growing up and the boundlessness of fantasy from one of the most brilliant storytellers in England.One winter morning, Oscar discovers that his parents have disappeared and he will be looked after by... a lion on the weekend. Leo allows the boy to eat as many cookies as he wants, reads his favorite book to him ten times and deals only with him, without being distracted, like parents, by work and phones.In addition, it turns out that the lion can transform into different animals, and all sorts of adventures await the couple! But before he leaves, Leo must make another amazing transformation…