After his parents are kidnapped, timid twelve-year-old Henry York leaves his sheltered Boston life and moves to small-town Kansas, where he and his cousin Henrietta discover and explore hidden doors in his attic room that seem to open onto other worlds.

In 1878, twelve-year-old Ida Kate and her widowed father welcome a mail-order bride and her baby to their Kansas homestead, but Ida Kate soon suspects that the bride is not the woman with whom Papa has corresponded.

Twelve-year-old Henry York, finally reunited with his family, works with them and the Chestnut King, the long-deposed and mythic leader of the faeren people, to destroy Nimiane and her forces of evil.