The stones of the riverbed are cold although a wane light touches them without end. When Castiel lays his hand upon one, it trembles faintly like an anxious shiver from a beast deep in sleep.
Castiel has learnt that things in Purgatory are unused to light and grace and touch. They sit in perpetual twilight, darkness never quite coming and never quite leaving. There is not enough light to feed the things that grow here and they hunger for Castiel.
When the water comes, finally, Castiel does not know how long he has crouched on the smooth stones, feeding them what is left of his grace. Purgatory has no measurable passage of time, but his vessel feels older, skin thinning to show each bone and tendon of his hand.
The water starts as a whimper, a hiss, the sound of Purgatory opening beneath him. Castiel sits very still as it rises, waves turning white as it runs fast over the old stone. Around him he hears a sigh, long and thin, and then the water slows.
Castiel has been waiting for what feels like a lifetime, his bones aching and his grace fading, and he slowly makes his way to the edge of the river. Its depth is unfathomable to him, the water opaque and black, even though he knows it should be only shallow, barely covering the stones he has spent an eternity staring at.
When he lets his hand hover above it the water below stills until it looks like glass. He knows if he were to touch it, it would consume him completely.
Castiel waits again. Promises over and over in his broken mind that if this place gives him what he needs, then it can have him.
There is a hungry groan from the forest around him, as it hears his thoughts, and the twilight begins to fade into night. Not the suffocating night of when he and Dean first came to this place, no not that night. This night has Castiel’s stars in it. It has them and he smiles, dry lips splitting and blood welling up from the cracks. Pain never felt so good.
His stars reflect on the window of glass below Castiel’s shaking hand. His heart trembles faintly in his chest, an unsettling feeling. His heart does not need to beat. It is not his heart. He wants to be back in heaven, but not his Father’s heaven. He does not want his siblings, or even his Father.
His family, small and broken, but still good, that is what he wants. That is his slice of heaven.
And at the same time he knows he can never go back, can never make it out of this place. Everything he has given it has been for the Winchester brothers. Sam has always needed Dean more than he need a broken angel, and so Castiel gave him what he needed most.
From his constellations Castiel conjures the man he almost destroyed completely. The man he betrayed. Below his shaking hand Sam Winchester appears.
His hair spirals out on imaginary currents below the glassy surface, splaying inky tendrils and he is just below Castiel’s reach. Castiel could touch him. He could. He knows he just has to let his hand drop a little lower. His fingers linger just above Sam’s peaceful face.
He hears the entirety of Purgatory hold its breath.
Sam has all he needs. He has his brother. Why should Castiel deny himself this one precious thing?
His eyes burn and sting and something wet and hot runs down his cheeks. He can taste salt at the corner of his lips. But he can’t really feel it. He is numb.
He is weak. He just wants this one last thing to be his.
And so he reaches down, his fingers braced for the chill of water and he hears a low whisper in his ear.
“Come to me, come to me,” it breathes, long and broken and begging softly. “I need you, if you can hear me, come to me – Cas, please.”
And without hesitation Castiel reaches for Sam, his voice lingering like the sweetest and most bitter song in the shell of his ear, the ringing of it filling his soul with untarnished love and he lets all his grace be enveloped into the darkness he so deserves.