Sam and Dean go on a good old-fashioned ghost hunt to track down a ghost with a penchant for lobotomies and plague masks.
A teenager by the name of Shawn watches his friend get killed by the plague-mask-wearing ghost with a drill, and runs out of the house with the stolen plague mask. While his trauma and not talking don't help Sam and Dean with the case very much, at least they know from his obsessive drawings of plague masks what they need to salt and burn when they finally track down the house.
But of course, it can't be that easy, and as soon as the plague masks burn and the doctor disappears, Sam and Dean realize they have a whole lot of other ghosts to worry about, so Dean kills himself real quick to talk to them.
Instead he gets a one-on-one with Billie, who has recently been promoted to the new Death. In typical Dean fashion, he makes a deal, Billie sends him back to his body after helping him clear out the rest of the ghosts in the house, and Sam and Dean head start to head home, only to be slightly detoured by an unexpected phone call.