Setting: Takes place in a universe in which Naruto is the one who left the village.
Notes: I don't believe I am the first one to think of this. There must have been someone before me.
Notes 2: Please do leave a review!
Sasuke knows what is happening.
Naruto looks at him, angry and excited at the same time, and Sakura just sort of stares at the ground, as if to pretend this isn't, can't be real.
Sasuke gets up from the hospital bed. He feels a rift in himself, Naruto, and the whole room when his feet touch the cold floor. It reminds him of home.
He is glad when Kakashi stops them just in time. It gives him the opportunity to imagine that everything is going to be all right again, someday, when Sakura's tears are dried and Naruto has found a way back to being himself. It is shattered as Naruto jumps off into the woods, not once turning around in their direction.
The next day he is gone. Sasuke searches the empty apartment with a strange hollow ache, dust particles dancing in the early morning light like small pieces of broken glass.
Naruto is gone.
Somehow Sasuke isn't really surprised but disappointed, disenchanted maybe.
The boy he finds in the Valley of the End is but a shadow of the Naruto they once knew, a distant memory made of pain and grief and hatred. Sasuke wonders if, perhaps, there would have been a way to avoid this, if there was a place out there where they could have stayed together.
There are clouds above them beginning to gather, piling up into a tempest befitting the finality of this battle.
"I want to make this a clean cut," Naruto says.
It doesn't feel clean, Sasuke thinks. It feels horrible, messy. We all are a big mess.
He doesn't remember much after that. A kick, a punch, two fates colliding. A supernova in the making. Then everything goes black, the rhythmic drum of the rain lulling him to sleep.
Two years later Naruto is like a vision, even less human than before. With his eyes Sasuke traces his face, the slightly paled skin, the set of his jaw, the cold glare that used to be as bright as the summer sky.
When they finally clash it's like a necessity, inevitable and oddly right. Space closes around them, the moment stretching endlessly. Something in Sasuke's core falls to place and the ghost of a smile is tugging at his lips.
"Sorry for making you wait."
But it's not the end, the nightmare goes on, blossoming into war and destruction.
And Sasuke can sense it like a deep fracture in his bone that there isn't much time left until they meet again for the last time; knows Naruto feels it too, because that's the way they've always been—one life tied to another, though the wound Naruto's desertion had left wasn't healed completely yet, scarring badly at the joint of two souls slowly merging.
From far away, at the outskirts of the village, resounds a roar and smoke is spiraling into the sharp air. The sky above the Hidden Leaf is burning.
Sasuke turns around to look at Naruto, dirty and bruised, and it's strange that he looks so out of place all of a sudden, so lost in the horror of politics and power. Almost like that small, lonely six-year-old of the day they first met.
He says something as his left hand clutches a bloody kunai, but it gets lost in the noise of people dying, and a world crumbling.
Sasuke approaches him with careful deliberation, sliding his sword out of its sheath.
"Let's finish this."
That day Naruto and Sasuke die far away from everything else, the moon flickering over them like it's about to break, but together as one.