Supernatural - Season 8, Episode 12: Soundtracks

Sam, Dean, and Henry enter what was once the Men of Letters' headquarters and is now a comic book store. 

Henry winds John's music box. Henry whistles in the motel room. Sam & Dean stand at Henry's grave. 

Henry walks outside and discovers it's the year 2013.

Henry tells Sam and Dean that he is John's father. Again, when Sam and Dean are standing in the graveyard.

The guys check out the Astro Comics shop.