Duality

Chapter 1

A/N: First story! Let me know what you think! This story will probably only be 3 chapters! It takes place in the middle of season 12.

It took awhile for the brothers to notice.

Not that they weren't paying much attention to their favorite angel. But the monster's act was surprisingly good.

Sam wondered how it was possible for a khan worm to trick not one, but two Winchesters by posing as their best friend.

With the three boys living so close together in the Men of Letters Bunker, Sam would've thought that it would be a piece of cake to notice if something was wrong with one of his brothers.

Dean was his big brother and had practically raised Sam. Despite his tough guy bravado, it was pretty easy for the younger hunter to notice anything off with him.

Cas on the other hand was a poor liar. Most of it was probably because he was an angel and wasn't used to doing human things like lying.

Even after the many years they had spent trying to teach the angel as much as possible.

He was still a terrible liar.

Sam guessed that this was why he didn't notice anything wrong with the angel. He at least decided that this was the excuse he was going to stick with.

Cas was a terrible liar. But the khan worm most certainly was not.

It was actually Dean who first noticed the problem. They had just gotten back from a hunt.

It was a strange one. A man had suddenly gone on a rampage; with ten murders under his belt, the Winchesters had originally assumed that the guy was a typical serial killer. After researching the case, Sam had discovered that the man had been a model citizen before hand.

The guy was a volunteer in his spare time, and even attended church regularly every Sunday. He was your average-Joe, suddenly turned murderer.

They suspected demonic possession at first. But after investigating the crime scenes and the man's house and discovering no traces of Sulphur, Sam, Dean, and Cas were at a loss.

That was until Dean remembered an old case.

It was a similar case many years ago during which a small monster was able to possess a person and make them do whatever the thing wanted.

Dean liked to avoid thinking about the case, as he had been one of the khan worm's victims that time.

Khan worms possessed a person by burrowing into their ear canals, leaving a trail of green sludge behind. The best way to drive the nasty creatures out of its host was by electrocution.

So once the Winchesters and their favorite angel got to the man, Dean making sure to grab the stun gun resting in the trunk of the Impala, the three got to work trying to rid him of the pest.

It was difficult considering the man was in the custody of the local police, but the three managed to work out a system. While Sam watched the door, Dean got to work trying to fry the monster out of the poor man. Cas was left trying to restrain the man and keep any sounds muffled so that the police didn't interfere.

Eventually, the khan worm was driven out and smashed under a dress shoe, courtesy of Dean and his pseudo-FBI getup.

After a quick cleanup and a reassurance to the clearly disoriented man that the three would do everything in their power to free the man, the brothers had assumed that the case was more or less over.

The Winchesters piled into the front seats of their Baby, Dean at the wheel as usual with Sam at his place in the front passenger seat. Cas took up his spot in the backseat of the Impala, and the three began the long drive back to Lebanon, Kansas.

But something was different. Looking back on it, Sam wasn't even sure when it could have happened. The three were right by each other's sides the whole time. It's not like Cas was really out of their sights.

The drive was mostly quiet, occasionally permeated by conversation between the two brothers. The radio blared its typical classic music, not that Dean would let anything else play out of his precious Baby's radio. The music was dimmed, a steady background against the rumble of the Impala's motor.

Their angel was unusually silent. He wasn't usually talkative, but this kind of quiet was uncharacteristic. The most he would contribute was one word answers or vague comments. This was Sam's first clue that something was wrong.

The younger hunter thought nothing of it, though. He had thought that maybe he was just ready to be home. He had never considered that it could be something like a khan worm.

Half way into the ride back, Dean glanced into the rearview mirror, shifting it slightly so he could see Cas. From his angle, he could only see the profile of Cas's face.

What he saw almost made him slam on the brakes.

Barely visible, a trail of dark green sludge was leading out of Cas's left ear. The angel, sensing Dean's gaze on him, turned his head, meeting the Winchester's eyes through the mirror.

"Is something wrong?" the angel questioned in his gruff voice.

"Uh, no not at all. Just checking up on you," Dean responded, shifting slightly in his seat and returning his sight to the road ahead. It was starting to get dark outside; the sun was dropping toward the horizon and the shadows grew long.

Sam noticed his brother grip the wheel tighter, clearing his throat and shooting a quick glance back through the mirror. The younger hunter turned his head, noticing that Cas had already turned back to gazing outside the back window.

Turning to look at his brother, Sam wondered if he had missed something. Were Dean and Cas having some sort of argument he wasn't aware of? But Dean didn't look pissed off. His body language always made it incredibly easy for Sam to tell when his brother was angry. This time, though, Dean looked uncomfortable. Nervous even.

"What? What's going on?" Sam nudged his brother's arm, wondering what he could possibly be upset about. "You guys having an argument? Something I should know about?"

"No, it's nothing," Dean shifted again.

Sam could see his brother's eyes keep drifting off the road and up to the rearview mirror, which made him a bit nervous. It would be stupid to get into a wreck on the way home because Dean wasn't watching the road. But he could tell that Dean wasn't just nervous. He was concerned.

Five minutes of awkward silence and furtive glances later, his older brother announced that he wanted to stop off to hit the bathroom. They pulled off at a decrepit old gas station in the middle of nowhere. Even Dean would say the place was sketchy.

Cas, of course decided to remain in the car as his human companions headed inside. As soon as the two brothers entered the rest area, Dean immediately turned to his brother, grabbing his arm and leading him off to a secluded area.

"What, what's going on?" Sam tried to break away from his brother, looking around to make sure there was no danger.

"Sam, we killed that khan worm right?" Dean asked, shoulders stiff and brows drawn together.

"Yeah, you crushed that thing. Remember, we mopped that thing off the ground," Sam wondered what his brother was getting at. There was no way Dean could have already forgotten about killing the monster. He himself had stomped on it.

"Well either that thing isn't dead, there's a second one, or Cas isn't telling us something. There's sludge coming out of his ear, man," Dean responded.

Sam froze, glancing out of a nearby window at where Cas was sitting in the Impala. Or where Cas should've been sitting in the Impala.

"Uh, Dean," Sam turned to his brother, "Cas isn't in the car."