A year ago Dean watched Sam walk away from the life. A few months later Sam dropped off the radar completely, his last words to Dean a scribbled note. I just need some time. Don’t look for me. I’ll call if I need you. Now it's 2009 and Dean finds Sam locked in a warded cell, guarded by the Campbells. They say he's running with demons, that they call him the Boy King. They say Sam's up to something big. Dean and Bobby confront a caged Sam who is cold and distant and far too knowing. While everyone tries to tell Dean that the brother he knew is gone, Dean is determined to find the truth. Along the way he discovers angels, broken seals, a runaway apocalypse, and visions of another timeline that burned up his brother's brain. Now all Dean has to do is figure out what Sam's endgame is and how to stop it, or risk losing Sam forever.