A reporter witnesses a brutal murder, and becomes entangled in a mystery involving a pair of Siamese twins who were separated at birth, one of them forced to live under the eye of a watchful, controlling psychiatrist.

When they were boys, Sam and Dean Winchester lost their mother to a mysterious and demonic supernatural force. Subsequently, their father raised them to be soldiers. He 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. Now, the Winchester brothers crisscross the country in their '67 Chevy Impala, battling every kind of supernatural threat they encounter along the way.