Supernatural, season 7

Castiel's godhood lasts exactly long enough to show what absolute power does to a good soldier - purged heavens, punished hypocrites - before the souls he took prove to be more than souls. The Leviathans, the first things God made and locked away for their appetite, ride Castiel to a reservoir and walk out in the water. He wades in; they spread.

The year is fought against an enemy with no lore, no bullet, no name to burn: things that copy anyone, heal anything, and buy what they cannot take. Their leader, Dick Roman, is a billionaire with a plan of horrifying banality - cure cancer, thin the herd, farm the species - and the season's paranoia is total, because the enemy owns the banks, the labs and eventually the news.

The costs are the point. Sam's wall is down and Lucifer walks his sleepless nights until a hospital and a stranger's grace quiet it. Bobby Singer - father in every way that counts - takes a bullet to the head working the Roman file, haunts the boys as long as a flask holds him, and is let go the hard way.

The weapon, assembled from a righteous bone and three bloods, works: Dick dies. But killing a Leviathan at detonation range has a blast radius - and it ends with Dean and Castiel gone, waking on the floor of purgatory itself, everything there already turning toward them.