Sam and Dean investigate a small town in Wisconsin where children are falling into comas for no apparent reason. The brothers discover that a witch is creeping into the bedrooms of the children and stealing their life force. While battling the witch, Dean recalls a past mistake that almost cost Sam his life at the hands of the very same witch, an event which has fueled Dean's protectiveness over Sam and his blind obedience to his father.

After Daniel Elkins, a vampire hunter and John's mentor, is murdered, Sam and Dean are surprised when John himself shows up to solve the case. John discovers the vampires have taken an antique gun, which has the power to kill all supernatural beings. The Winchester family sets out to retrieve the gun from the vampires so they can use it to kill the demon that took Sam and Dean's mother.