Daisy Fitzjohn lives in a secluded mansion called Brightwood Hall, and has never once set foot outside its grounds. Daisy and her mother have everything they need within Brightwood's half-ruined walls, including Daisy's best friends: a talking rat named Tar and the ghost of a long-ago explorer who calls herself Frank. Then her mother disappears, and James Gritting arrives on the estate, claiming to be a distant cousin. As the days tick by Gritting becomes more and more menacing. He wants Brightwood for himself, and he will do anything to get it.