Supernatural: Bone Key (Supernatural Series, 3)

Twenty-two years ago, Sam and Dean Winchester lost their mother to a mysterious and demonic supernatural force. In the years after, their father, John, taught them about the paranormal evil that lives in the dark corners and on the back roads of America . . . and he taught them how to kill it.
Sam and Dean are headed for Key West, Florida, home to Hemingway, hurricanes, and a whole lot of demons. The tropical town has so many ghouls on the loose that one of its main moneymakers has long been a series of ghost tours. But the tours are no more, not since one of the guides was found dead of an apparent heart attack . . . his face frozen in mid-scream. No one knows what horrors he saw, but the Winchester brothers are about to find out.
Soon they'll be face-to-face with the ghosts of the island's most infamous residents, demons with a hidden agenda, and a mysterious ancient power looking for revenge. It's up to Sam and Dean to save the citizens of Key West . . . before the beautiful island is reduced to nothing more than a pile of bones.