Penelope Taberner Cameron is sent to her aunt who lives on a farm in Derbyshire. The farm, known as Thackers, has been owned by the Taberners for generations, but was previously the residence of the infamous Babington family. Penelope begins to suffer from hallucinatory visions of the house's former residents and is soon thrown back into the 1500s, where she meets the Babingtons. She discovers that they are plotting to rescue Mary, Queen of Scotsland from prison and put her on the throne of England instead of Elizabeth I.