While investigating the disappearance of a missing man, Sam and Dean have to break in to the place where he disappeared, but they get caught, and Dean is shot and killed by the owner. When Sam wakes up the next morning he is shocked, Dean is alive, but as the day continues Sam realizes that they are re-living the previous day so he tries to stop Dean from getting shot, but he fails and Dean dies again... and again... and again, so Sam has to learn how to continue on without his brother.
Sam Winchester is a college student bound for law school, determined to escape his family's past - unlike his older brother, Dean. Ever since they were little their father has been consumed with an obsession to find the evil forces that murdered his beloved wife, and recruited his two young sons to help them. They have grown up as hunters of the supernatural. Sam escaped this way of life after high school, and now has a happy life with his girlfriend, Jessica, and a promising future career. Dean, however, stayed behind with his father to join him in his "hunting".
After Dean arrives for Sam's help when their father goes missing, Sam must join his brother to find him. His one weekend trip to search for the missing John Winchester becomes an ongoing quest after a horrible tragedy ruins any thought of a happy life for Sam.
The two brothers, bound by tragedy and blood to their mission, travel across the country encountering terrifying and dangerous forces most believe to be nothing but superstition and folklore, such as the Lady in White, the Indian beast known as the Wendigo, Phantom Travelers who cause plane crashes, Bloody Mary, and many more.