Based on this writing prompt from Facebook:

After a long night of tossing and turning in your bed, you realize sleep is not in the cards today. You dress and make your way to the 24 hour store to do some 3 am shopping. Walking the aisles, inspecting products you otherwise wouldn't notice the power flickers twice then goes out completely. A few aisles over you hear what sounds to be a few cans fall from a shelf. Taking a deep breath you begin again down the aisle and the lights flicker back to life. You look around and find the store a disaster. What happens next?

"H-Hello?" I stammer, looking around for anyone who could tell me what's going on. "Is anyone here?"
There's just silence. I try not to panic. It's nothing. Just a quick power outage, that's all. Maybe the wind picks up, knocked out the power for a few seconds. It would explain how everything ended up on the floor. I take a deep breath and quickly walk to the registers to ask for help, but they're empty. I could have sworn I saw someone in here when I arrived. Maybe they're switching shifts. I don't take the time to find out. Instead, I head to the exits. I can get what I need tomorrow.
The doors aren't opening. They're supposed to be automatic. They've always been automatic. It's the power failure, isn't it? I sigh. There has to be a manually operated emergency exits somewhere here. I stay close to the walls, looking for the red word lighting up the walls somewhere. I find a door finally, but the sign isn't lighting up. I push the metal bar and try to open the door, be it won't budge. When I come back tomorrow, I'll have to complain about this. What if this had been a fire? No one could have gotten out of this door. To my surprise, none of the doors open. They aren't electric, so the power outage wouldn't affect it, and the door handle isn't stuck, either. I could turn them all easily.
What is going on? I whip out my cell phone to call for help. "No service," it reads. I groan and put it back in my pocket. Seriously? Now this is just getting annoying.
"Hey!" I tell as loud as I can. "Okay, you got me! It's over now! You can let me out!"
I wait for the trickster that decided this would be funny to come out, but no one does. Now what? I can't escape, and I can't get help. It seems I'll have to help myself.
The first thing I do is search the store for anything I can use as a weapon, should I need it. Finally, I find set of iron cutlery. I grab a knife to put in my pocket, and another for my hand. I don't know what to expect, so it's best to be prepared.
I walk around the store, hoping to find something I've missed, but nothing has changed. I'm careful not to step on anything that's on the floor as I do so. When this is over, I don't want to have to pay for anything I break.
I notice some movement by the window. I run over to it, hoping to find someone that I can signal for help. By the time I reach it, they're long gone, whoever they were.
Suddenly, I hear the loud crash of shattering glass. Logically, the best thing to do right now would be to run as far from the noise as I can, but curiosity gets the better of me. I find my way to the source of the sound, which I know already is the sliding glass doors.
I see three people standing on the remains of what used to be a perfectly good door. One of them is a tall man, at least a foot taller than I am. His perfect hair is long and, well, perfect. The man next to him is shorter, with a nice looking jacket over his plaid shirt. The third is the shortest, though still easily taller than me. His trench coat nearly reaches the floor, covering his fancy suit. Why does he seem so much more dressed up than his friends?
The tall man spots me, and I don't know what to do. I should I run? They did just smash through a door; they don't seem like the best people to be hanging around with. Still, at this point, I'm desperate. I'll take any help I can get.
"Hey!" the tallest man shouts, looking over at me. His friends both look too, and I take a step back, not sure I want to get close to them.
"You!" the middle-heighted man calls, reaching into his jacket. Oh my god, he has a gun. He points his pistol at me without hesitation. "What are you?" he demands.
I take another few steps away from them. He just threatened me. He just threatened to shoot me! I whimper, holding back tears. This has been a really stressful day.
"Dean," his trench coated friend interrupts, pushing his arm lower so his gun is aimed at the floor. "She's human."
"Wha-What's going on?" I ask quietly, my fear obvious in my voice. Of course I'm human. I may not be the prettiest girl in the world, but I'm still recognizably human!
"We could ask you the same thing," the tall boy says. He walks towards me, and I step away. Noticing my discomfort, he backs up as well.
"We're not her to hurt you," he assures me. I glance at the boy the trench coated boy called Dean, and the tall man seems to notice. "Um, yeah. I know it's hard to believe, but we're actually here to help you."
"H-Help me how?" I ask.
"We're going to stop whatever is doing this," he promises.
"Sam, let's go find the salt," Dean says. The tall boy, who is apparently Sam, follows Dean in search of... Salt?
"Hello," the trench coated man greets me.
"Hi?"
"My name is Castiel," he tells me. Weird name. "And you are?"
"Why would I tell you what my name is?"
"Because I told you mine," he reminds me, sounding confused. "That's how humans do it. I tell you my name, you tell me yours."
"I don't think that includes people with guns that barge into locked down stores."
"I don't have a gun," he tells me. He opens up his trench coat to show me. "Just my angel blade."
He holds up his small metal "angel blade," and I just look at it for a moment. What the hell is an angel blade? Why does he have an angel blade? Why does he have a blade at all?
"Why is it called an angel blade?" I ask him. It's probably not the best time to be asking questions like that, but I don't care. Curiosity killed the cat, but satisfaction brought it back, after all.
"Because it's my blade, and I'm an angel."
I just stare at him for a moment. What the hell? Then I start laughing. This is hilarious! This whole thing has been some elaborate prank for one of those tv shows, hasn't it?
"Ah, yeah, that's great," I say, still laughing. "Where are the cameras?"
Castiel looks confused once again. "I don't understand that reference."
"It's not a reference, buddy, unless I'm referencing real time."
Sam and Dean return then, each carrying a few cases of salt.
"What cameras?" Dean asks as he and Sam pour salt all around the broken door.
"The ones that are filming this," I reply. "You know, the ones that they set up for those ridiculous prank shows."
Sam and Dean share a look that reads "what the hell is this girl talking about?"
Suddenly, all the windows and the one remaining glass door breaks, and the lights all shatter. I begin to hyperventilate. Why are they still going? I figured it out. They can stop the cameras now and come on out.
"What the-" Dean begins, but he's silenced as a other man suddenly appears in front of us.
This man has long hair like Sam's, but his is slicked back more. He's much shorter than the other three. He's only about my height, actually. He's wearing a big smile as he looks around at the four of us in front of him.
Dean is the first to speak.
"Dammit, Gabriel, you better not have messed with my car!"