Sam and Dean Winchester have spent their lives on the road, battling every kind of supernatural threat. Over the years, after dozens of bloody adventures, they have faced everything from the yellow-eyed demon that killed their mother to vampires, ghosts, shapeshifters, angels and fallen gods. With the help of allies--both human and supernatural--they've discovered that every threat they vanquish opens a new door for evil to enter in.  Visitors passing through Brownsdale, Kentucky are often never seen again. The locals claim that it's easy to fall victim to the vast local caves if explored unaided, but when two young girls go missing Sam and Dean set out to investigate.  As the brothers start to suspect something far more sinister in the town, and possibly lurking in Mammoth Cave, they realise that someone is determined to protect the town secret--even if it means killing Sam and Dean himself.   A brand-new Supernatural novel, set during season 10, that reveals a previously unseen adventure for the Winchester brothers,  from the hit TV series!