The protagonist is Tom, a young chimney sweep, who falls into a river after encountering an upper-class girl named Ellie and being chased out of her house. There he drowns and is transformed into a "water baby",[2] as he is told by a caddisfly—an insect that sheds its skin—and begins his moral education. The story is thematically concerned with Christian redemption, though Kingsley also uses the book to argue that England treats its poor badly, and to question child labour, among other themes.