Season 5's horrific finale left Dean alone, as Sam descended into Hell. Now a different man, Dean vows to stop hunting and devote himself to building a family with Lisa and her son Ben. Then, mysteriously, Sam reappears, drawing Dean back into hunting. But all is not as it seems: Sam is different. A soul-shaking discovery proves Dean's suspicions: this is Sam - but not all of him. How the Winchesters confront this greatest challenge yet to their powerful bond is the troubled heart - and soul - of the profound and thrilling Season Six. As the brothers struggle to reunite, they must also battle deadly supernatural forces: demons, angels, vampires, shape-shifters. And a terrifying new foe called the Mother of All.