22 years ago their mother was killed by a demon in a fire. Ever since then John Winchester showed his two sons, Dean and Sam how to hunt everything that hides in the dark. When John goes on a hunt for more than 10 days, Dean goes to get his brother at Standford to try to find their father. Ever since that day Sam decided to follow his brother on the dusty back roads of the United States.
Season 2 SPOILERS, don't read if you haven't listenned to any episode of the second season.
When they father trades his life to get Dean back in his body he asks Dean to take good care of his baby brother. Dean feels guilty of keeping the secret from Sammy and Sammy doesn't want to go back to school because he feels guilty of doing everything to pull a figth with John the last time he saw him.
