Sam and Dean 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 Lucifer and the Leviathan. 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. In the show’s eighth season, their supernatural hunting expedition led them directly into an age-old power struggle involving the King of Hell, legions of warrior angels and a series of divine trials to prove themselves worthy of sealing the Gates of Hell forever. With the help of their protector, the angel Castiel, who’s been cast out of heaven with the other angels, Sam and Dean’s lifelong quest to set the supernatural world right again will take everything they’ve got.