Supernatural, season 4

Dean wakes in his own coffin four months buried, and the thing that pulled him out announces itself in a barn full of sparking lights: Castiel, an angel of the Lord. Heaven is real, its soldiers walk in borrowed bodies, and they raised Dean because work needs doing - sixty-six seals stand between Lilith and Lucifer's cage, and she has started breaking them.

The year runs the war in parallel with the wound: what happened to Dean in hell - thirty years on the rack, ten holding the blade - and what Sam did in the four months alone, which is Ruby, demon blood, and powers he can aim. The brothers keep each other's secrets until they cannot, and the season's real fracture is not angel-against-demon but Winchester-against-Winchester: a phone message, a fight in a hotel room, Sam's hands closing on Dean's throat.

The angels, it develops, are not uniformly the good news - some want the apocalypse on schedule, and the seals are being spent, not defended. It ends in a chapel: Lilith the final seal, killed by Sam's borrowed strength exactly as designed, Ruby's work finished and rewarded with the knife, and light climbing out of the floor. The last seal was never a lock. It was a door, and the brothers opened it.