Supernatural, season 9

Sam is dying from the trials, and Dean's solution is the season's original sin: an angel - calling himself Ezekiel - possessing Sam without Sam's knowledge, healing him from inside, with Dean carrying the secret through months of small lies. The angel is not Ezekiel. Gadreel, the guard who let the serpent into the garden, buys his rehabilitation from Metatron with errands, and one of them is Kevin Tran, dead on the bunker floor by Sam's borrowed hands.

The fallen angels are the year's weather - factions under Bartholomew and Malachi, Castiel human for a stretch (theft, a stolen grace, the show's best homeless interlude) - and Metatron writing himself a hero's arc from heaven's empty typing pool.

Dean's answer to powerlessness is the arc that pays for seasons: the Mark of Cain, taken from the first murderer himself, and the First Blade it powers. The Mark wants. It steadies his hand and hollows the rest, and Crowley - half-addicted to human blood since the botched cure - watches it work like a man tending an investment.

It ends with Metatron ascendant and careless, Gadreel's redemption bought with his own life, Castiel breaking heaven's door - and Dean dead on a bed in the bunker, Metatron's blade through the chest. Then the last minute: Crowley talking to the body about a story Cain never finished, and Dean's eyes opening black.