A 10-year-old boy named Oscar has cancer. He recounts his life in the hospital, where the children are cared for by nurses known as the "Pink Ladies." For Oscar, one of the Pink Ladies—Granny Rose—becomes a second mother. When Oscar learns he has only twelve days left to live, Granny Rose proposes a game: each day will count as ten years. In letters addressed to God, Oscar describes each day he lives, speaking about the various stages of his imagined life.