"It's not a demon, or a shape shifter." Sam was positive. "It's a ghost."

"But how?" Charlie protested. "The train can't be haunted, although that would be way cool! This was happening long before this train was built."

"Maybe it's something on the train." Dean mused. "Or a ghost tied to one of the older stations hitching a ride on one of the passengers."

Charlie nodded. "Like that ghost at your old high school."

Dean sighed. Chuck and his damned books. "Yeah, like that."

"If we could find out where it all started – " Charlie pulled out her laptop. "Wi-fi?"