When Sam and Dean Winchester were just little kids, their mom was killed by something "supernatural." Their father's life and their lives were never the same after that. After that incident, their father raised them to be warriors and started to take an interest in the "supernatural." 22 years later, Sam and Dean are grown up and one day their father goes on a hunt and disappears. Sam and Dean try to find him but all they find is their dad's book containing information about evil entities. Sam and Dean continue to search for their father and along their way they try to help anyone with a "supernatural" problem with the help of their dad's book.