S04E19: 'Jump The Shark'

The Winchesters head to Minnesota after being contacted by a boy called Adam Milligan who claims that he is their long-lost brother.

Dean is instantly suspicious, thinking that it is a trap set by a demon or a shapeshifter, while Sam is more open to the possibility that John might have fathered a third child while on a hunting mission in the area.

Despite their differences, the brothers join forces to investigate the disappearance of Adam's mother, which they believe is linked to a spate of grave robberies previously investigated by John.

A second disappearance and a string of fresh cases soon leads them to suspect that the demon responsible for the gruesome crimes managed to escape their father and is now back for revenge.

Elsewhere, the boys' clash over whether John was right to keep Adam a secret from them, before an unexpected twist forces them to reflect on their own relationships with their father.