In Heaven, there is no sense of time.
There is no way to tell whether it is Monday or Tuesday. There is no night, no day, no time. There is just now. There is but a moment.
But Castiel knows.
He knows every second, because he was taught by the Winchesters. He was taught the way to live on "the slow path," and he knows how long a minute can seem when you are not with those you love. So he knows that it was exactly 5:13 am on a Wednesday morning when Naomi summons him into her office.
"Castiel. We have a special task for you."
"Yes, Naomi?" The brave little soldier answers, his shoulders straight, his eyes dead.
"You are to kill Dean Winchester."
Castiel looks up, a tiny spark flickering in his eye. A tiny spark of what once was. "I will not kill him, Naomi."
"You must. It is an order." The woman stands, walks around her desk, and crosses her arms. "You will do what we tell you to. We saved you. We make you."
"I will not kill him."
"You will."
Suddenly they are in a large room, more like a warehouse. The walls are grey. The ceiling is high. Castiel turns to face Naomi, but she is not there.
Instead, Dean stands there.
The look on his face is one of sheer terror. "Cas...Cas, no, please!" He backs away from the angel. Instinctively, Castiel slides his weapon from his side. He looks up.
"NAOMI! WHY ARE YOU DOING THIS?"
Dean freezes, his face frozen in fear, his hands up. Naomi lets out a lengthy sigh as she walks towards of him. The only sound in the room is the clicking of her shoes against the metallic tile. "He is not the real Dean, Castiel. Just a prototype." She smiled, her head tilting to the side just a bit. "You must practice. You must know what it feels like to have him in your hands. You do not want it, now. But you must kill Dean Winchester."
Castiel's eyes burn red hot, and he walks towards her. "Who is to say I will not kill you first?" He spits at her, his words venom on his tongue.
"Oh, Castiel." She looks at him with something like pity in her eyes, then shakes her head. "You must do this for Heaven. We are depending on you."
With that, she is gone.
Maybe he can fly away.
When he tries, an electric current shoots down his wings, stinging his heart.
"Castiel, you should know that we would predict you would attempt to escape." Naomi's voice echoes eerily across the room, and there is no way for Castiel to find where she is. He growls menacingly under his breath. "Do not act out. We will reprimand you." And again, a shock shakes the angel to his core.
"ALRIGHT!" He yells, his voice low. With that, the shock subsides, and the angel begins to feel normal again. Except that this is not normal, this is anything but normal. Castiel is being forced to kill his best friend, possibly even the man he loves, for what could be the first of many trials.
Step,
step,
step.
"Cas, no, please don't do this. Please. I'm beggin' ya, buddy. Ple-"
It is 6:17 am when Castiel kills Dean Winchester for the first time.