Two big things happen to the Winchester brothers on the next episode of "Supernatural". Called "Dark Side of the Moon" and airing on April 1, the episode sees them dead and returning to their childhood home to meet their deceased mom.
Ambushed by angry hunters, Sam and Dean are shot and killed and sent to Heaven. Castiel warns Dean that Zachariah (guest star Kurt Fuller) is looking for them in Heaven so they need to lay low while searching for an angel named Joshua (guest star Roger Aaron Brown) who can help them since he talks directly to God. While searching for Joshua, the brothers run into some old friends and family members.
Mary Winchester aka the mother of Dean and Sam are portrayed by Samantha Smith again although in the flashback episode earlier this season, the role was tackled by Amy Gumenick. Mary died in the pilot episode when she was killed by Azazel. She appeared as spirit later in episode "Home" of season 1 and again as a person in alternate world in season 2.