Twenty-seven years ago, Sam and Dean Winchester lost their mother to a mysterious and demonic supernatural force. In the years after, their father, John, taught them about the paranormal evil that lives in the dark corners and on the back roads of America... and he taught them how to kill it. On the hunt for Lucifer, the boys find themselves in a small town in South Dakota where they meet Don - an angel with a proposition... Don sends them a very long way from home, on a mission to uncover the secret Satan never wanted them to find out.