As Time Goes By (S08E12)

Sam and Dean are stunned when a man who claims to be their grandfather, Henry Winchester (guest star Gil McKinney), suddenly appears in their hotel room demanding to know where he can find John Winchester. Henry has time-traveled to stop a demon named Abbadon (guest star Alaina Huffman) and was looking for John's help. Through Henry, Sam and Dean learn more about their father and the Winchester blood line. (Warner Bros. UK)