Kansas, 1896. After a tornado destroys the Gale family farm, 11-year-old Dorothy goes missing. As the days pass by, the Gales are increasingly terrified the worst has happened. But when the girl turns up unharmed four days later, the townsfolk breathe in a sigh of relief. That is, until Dorothy herself relates her account of the events that took place after her disappearance.

In vivid detail, Dorothy describes a fantastical land and its magical inhabitants, from the scarecrow, the tin man, and the cowardly lion to the wizard and the witch. Her recollections are not only regarded as delusional, but also as pagan and diabolical in nature, especially when the body of a local spinster is found. Making connections between the evil witch Dorothy claims to have defeated and the ill-tempered old crone, authorities find what they believe to be incriminating evidence, sentencing Dorothy to the Topeka Insane Asylum.

When 28-year-old psychologist Dr. Evelyn Grace Wilford arrives at the asylum to interview Dorothy, she begins to wonder if Dorothy truly committed the crime or if something unfathomable has really occurred.

In a small town full of insidious secrets, will Evelyn be able to save Dorothy from her terrible circumstances? Or is something menacing lurking just out of sight?