In the Beginning

S4, E3: Dean is transported back in time and is shocked when he lands in Lawrence, Kansas. However, that shock turns to amazement after he runs into a young John Winchester (guest star Matthew Cohen - "South of Nowhere," "Medium") and Mary (guest star Amy Gumenick - "Greek") who have just fallen in love. Dean isn't sure why he was sent back so he begins to enjoy the time with his parents and newfound grandfather (guest star Mitch Pileggi - "The X-Files," "Stargate: Atlantis"), who may be hiding a secret that is key to Sam and Dean's entire predicament.