Chapter Text
It all started with a feather -- just one. Blue-black and glossy, it hung from Cas' trenchcoat for almost a day before being discovered and plucked off by Dean.
"Hey Cas, are you molting or somethin'?" he joked, holding it up for inspection. Cas denied it after a long, calculating look, Dean shrugged and dropped the feather in the grass, and they soon forgot all about it.
But three days later, two feathers appeared, stuck in the collar of Cas' shirt. They were identical to the first feather, and he couldn't help feeling a little uneasy as he discarded them. But he didn't tell Dean or Sam, not until he looked in the mirror the next day and found two more, poking out of his sleeve. They discussed it at length and got absolutely nowhere. It couldn't be Gabriel's doing (they hadn't seen him in months), Balthazar wouldn't play tricks like that (his sense of humor was much darker), there were no witches in the area (that they knew of), and besides, Cas felt fine -- on and on and on. There was just one thing Cas neglected to mention: since his release from Purgatory a few months back, his Grace had been… off. He could only describe it as a sort of flickering or warping, like a guttering candle flame. It was probably a result of being in Purgatory for so long, but he figured it wasn't worth mentioning, so he let it go. What could they do about it, anyway? Whatever the problem was, it would likely sort itself out...
He was wrong. A few days later, three more feathers showed up, on his arm this time- and they weren't just stuck to his clothing, they seemed to be growing straight out of his skin. Horrified, he did the first thing that occurred to him: he grabbed them by the shafts and yanked. This was a mistake. Pain rang through his arm like a gunshot and blood spattered across his shirt. He yelled and crumpled to the floor, still clutching the bloody feathers in his hand. That was how Dean found him when he ran into the room moments later, alerted by the shout.
"Cas, you okay?" Dean tried to turn Cas onto his back, but the angel gasped and recoiled from the touch; he pulled his hand back to find it smeared with blood. "What did you
do?
" He leaned over Cas, calling his name, until his eyes flickered open; and then Dean wished they hadn't. The blue eyes that focused on his face belonged to neither Castiel or Jimmy Novak. There wasn't a flicker of recognition in them and it sent a horrible cold shiver down his spine. "Cas...?" Dean said tentatively. The angel blinked once, twice, and then he was himself again. He looked up at Dean with both embarrassment and surprise.
"Dean...?"
"Right here, buddy." Dean gave him a shaky smile. But then his gaze fell on the mangled feathers in Cas' hand. "What the hell's happening to you...?" he muttered, more to himself than to the angel. Cas looked down at the feathers, then at the blood seeping into his sleeve.
"... I don't know."