Supernatural: Season 4, Episode 19

4 - 19: Jump the Shark

A 19-year-old boy named Adam calls Sam and Dean looking for John Winchester, claiming to be his son. Dean and Sam meet Adam, assuming he's a demon trying to lure then into a trap. However, they find out that John was indeed the boy's father and Adam tells them of his "normal" upbringing, which infuriates Dean.