A/N: Written for the quote-prompt: "John: "Killing this demon comes first. Before me, before everything." Sam: "No sir. Not before everything." " at spnquotefic over at LJ.

I promise, one of these days I'm going to get back to my WIPs. One of these days. ((shifty eyes))

Warnings: SPOILERS for season 4. Blood, gore, metaphor-abuse.

Disclaimer: I don't own Supernatural or any of its characters.

For You

It's only a moment.

Ruby is holding out her arm, knife slicing slowly, sensuously, across the skin. She's looking at Sam the whole while, dark eyes dancing with promise.

Just a moment.

He thinks (because by now he's got a right to be mellow) that he walks a thin line: a line that divides Ruby and blood and the world from Dean and love and desperation. Sometimes he isn't sure whether he's walking the line at all; if he isn't just falling headlong into either side.

(because if the world is wrong then Dean is right but if Dean is wrong the world is right)

Other times the line is dread, a tiny black parasite that twists in his guts as he leaves Dean in the dead of the night to exorcise another demon; as he ignores Ruby's calls and sidles into the Impala with his brother. It tells him, always: the other side is right.

He thinks that's the cruelty of walking the middle line.

Then the moment passes; as Ruby's blood wells and flows (red and thick like a glacier on the brink of a cascade), he realises there is no line.

Dean and the world: they're the same (they have always been) and he can save them both.

He can.

He grabs Ruby's arm with eager hands and lowers his mouth to the wound, half-salivating already for the blood that's going to give him the power to save the world-brother-world. He sucks, breathing in the scent of it even as he -

But it -

It tastes different.

Sam frowns, and looks up. It's not Ruby's arm he's holding anymore, but Dean's. His brother is looking at him with mingled anger, sorrow and disgust, and Sam just - stares, hardly daring to breathe, even as Dean's blood drips from his lips.

No, Sam, Dean seems to say, then Sam feels a sharp, terrible pain just under his ribs that soon flares into white agony - Dean's ... Dean's stabbed - but, but, Sam was going to - why can't Dean understand -

Sam throws his head back and screams, and when he looks at Dean again, it's not Dean who's grinding a knife into his chest, but Alistair.

The demon grins, and Sam's screams continue to echo off the iron walls.

Finis