Sam gets an e-mail from his old school friend Becky telling that her brother, Sam's friend Zach, is arrested in St. Louis for the alleged murder of his girlfriend. Zach claims that he was in another place at the same time, but the surveillance camera had taped his image in the crime scene. Sam convinces Dean to drive to Missouri, to check out the apparent doppelganger case, posing as US Marshalls. Once there, they find that a shape shifter is killing and hurting people in the neighborhood. When the ghost demon takes the form of Dean, things get complicated for Sam who soon realizes it's not his brother.
—KGF Vissers