A/N: So I am really excited to post this chapter because this is where things finally start to make sense! Well, kind of. Anyways, read on, my friends! :D Disclaimer: I do not own Supernatural.

Castiel bolted awake, gasping for air. The angel gripped at his chest where his heart was pounding harder than normal. He felt as though he had just run a marathon. Cas frowned; he was unsure of what a marathon actually was, but the phrase seemed to fit the situation. He glanced around and found that he was in Dean's bedroom. A light blush warmed his cheeks as he realized that he was also lying on Dean's memory foam mattress. Cas sat up with a grunt and swung his legs over the side of the bed. A strange weightless sensation took over the angel's body and he stumbled, disoriented. Turning, Cas was shocked to find that his body was still lying on the bed.

Cas could hear whispers all around him, faint and breathy. A cold sweat ran down his body and he found himself walking out of the room. His feet moved on their own, setting him on the path to their desired destination. Castiel was too busy watching his feet and didn't realize that he was about to ram into a desk. As his lower body collided with the mahogany wood, he bent forward and slammed his chin on the corner of the desk. Groaning in pain, Cas lifted himself up on wobbly arms and looked up at his reflection in the mirror. He frowned in confusion; there hadn't been a mirror in the middle of the library before. Heaving himself up, Cas circled around the corner of the desk, his arms anchoring him to the desk's surface.

The longer he stared at the shiny surface of the mirror, the wider the ripples within became. Cas watched in amazement as a shadowy figure suddenly became visible. It pushed against the surface, sending the ripples into a frenzy. Cas panted; the breath that had been knocked out of him had yet to return. The shadow now stood in front of the mirror, its outline trembling. "Who...who are you?" Cas wheezed. He tried to take a step, but his knees went weak and he pitched forward. The angel saw the floor coming towards his face and squeezed his eyes shut. He was caught by a pair of strong arms and his face was pressed against a broad chest. "Careful, angel," murmured a low, rumbling voice in his ear.

Cas shivered and lifted his head to find a pair of strikingly green eyes staring down at him. Cas could have sworn that his heart was in his throat; he'd know those eyes anywhere. "Dean," he breathed. The man quirked the corner of his mouth up in a half grin. "Hey, Cas," he said. The angel didn't understand the torrent of different emotions that threatened to overwhelm him. The man holding him up was indeed Dean Winchester, but there was something off about him. Cas pulled back to look him over, which the man allowed with a sly smirk. His hair was slightly longer than Dean's and he had a neatly trimmed beard. Freckles and scars dotted over his tanned skin, which was bloody in some areas.

He wore dark bootleg jeans and a blood splattered green shirt under a ripped open red plaid button down. A silver ring flashed in the light on his right hand and a dagger's handle was nestled in a holster strapped to his thigh. "You done checking me out yet or should I give you a little more time?" the man said in an amused sarcastic tone. Cas pouted, not understanding what the man meant by "checking him out", and ducked his head to avoid Dean's eyes. Clearing his throat, Cas moved to extract himself from the other Dean's grasp, but the replica simply chuckled and lifted the angel to his feet with ease. Cas stood awkwardly with Dean's hands gripping his biceps with gentle pressure. The other Dean winked, patted Cas on the arm, and turned to walk towards the bookshelves.

Castiel blinked and he frowned, trying to decipher exactly who this man was. "You keep frowning like that, you'll end up getting wrinkles," Dean quipped, bending to pick up a book from the floor. The angel's mouth fell open in surprise; how had Dean seen him frowning when his back was turned? Dean chuckled and looked back at Cas from over his shoulder. Blue met green and Cas' heart fluttered. 'Strange,' he thought, 'Why am I suddenly feeling such...sensations around Dean?' Puzzled, Cas looked up at the mirror image of Sam's brother with squinty eyes of suspicion. Before he could speak, however, Dean quickly scooped up another book and made a noise of triumph.

"Found it!"

"Found what?"

Dean hurried back over to where Castiel was still standing awkwardly and held the open book up in excitement. "This," he said, jabbing the pages of the book with his index finger, "My explanation." Cas' brows rose doubtfully and Dean clicked his tongue in disapproval. He shifted so that Cas could see the pages and pointed at the words and images again with great enthusiasm. Scanning the pages, Cas recognized the words and realized that Dean had picked up the book he had been reading before he'd passed out. He took the book from the clearly pleased Dean and studied the pages with an intense expression. "See, the mirror- that big, ugly thing over there," Dean said pointing, "It's not a mirror at all; it's a rift."

Castiel's eyes widened in understanding and Dean grinned happily, ecstatic that the angel was following along. "But rifts don't usually form within physical objects like mirrors. So, I figured that this mirror was once the famous fabled mirror from the Chinese novel The Dream of the Red Chamber. In the novel, it was a double-sided mirror that shows truth on one side and lies on the other. I think that something tore a rift in the mirror and forced it to become a weird version of a dimensional doorway," he explained animatedly. Floored, Cas stared at the gray-scale picture of a person falling from a rift. It sent a cold shiver down his spine; he imagined that his Dean had had a similar experience.

The excitement faded from the other Dean as he watched Castiel's expression of awed realization shift into one of a grave sadness. The angel slumped against the desk and slid to the floor, the book lying sloppily on his lap. Dean furrowed his brows in confusion and sat down on the floor next to Cas. "Cas, you okay?" He wasn't expecting the angel to flinch at his statement; it sent a pang of guilt through his heart. Cas sighed and ran a tired hand down his face. "You're not from this dimension," he stated flatly. It wasn't spoken as a question, but Dean nodded anyway with a wary expression.

Cas stared straight ahead with a faraway look in his eyes. "I can't help but wonder if you are from the reality that my Dean was thrown into," he said,"I don't understand why you shoved him into that mirror- or rift- and I don't know why you are the one here and not him." The words were harsh, but Cas' voice was soft and held no hatred- only weary sadness. The other Dean wasn't sure how to respond; he honestly didn't think that he would get as far as he did with the angel. He was silent, pondering over Cas' words with a small frown. Eventually, he heaved a sigh and nudged Cas' knee with his.

"In order for me to tell you why, I'm gonna have to tell you the whole story from the beginning. Get comfortable, angel, cause it's a long one," he said. Castiel squinted at Dean and tilted his head, a bit befuddled. Nonetheless, he shifted into a more comfortable sitting position and looked at the other Dean attentively. "I'm listening...human," he said. Dean blinked in surprise then burst out laughing. The back of his head struck the desk as he threw it back in laughter and he cursed, nursing the spot with his palm. Calmly, Cas reached over and lightly touched his fingers to Dean's cheek. Instantly, Dean stopped rubbing the sore spot and stared at Cas in amazement. "Holy crap, you really are an angel," he mumbled.

While the other Dean and Castiel conversed in the safety of the bunker, Sam Winchester of the other reality was not doing well at all. After he had said goodnight to the Dean downstairs, he had fallen asleep almost immediately on his bed in the corner. He had tossed and turned as another vicious nightmare gripped him and tortured his subconscious. Bolting awake, Sam had curled up against the wall, his tangled sheets wrapping around his feet like snakes. Sam sighed as his shaking body slowly began to still and calm. He heard footsteps coming up the stairs and he tensed, afraid that it was Dean. It turned out to be a very sleepy Cas, who shuffled by his door with a huge yawn. Cas paused by his doorway and peered at Sam through half closed eyes.

"Sam?"

"Hey, Cas,"

The moment that Cas heard the tremble in Sam's voice, he was crossing the room, clamoring onto his bed, and pulling Sam into a hug. Sam gratefully hugged him back, though he felt guilty keeping his friend awake. "Did you have another nightmare?" Cas whispered. Sam hesitated and Cas' hold tightened around him. Sam nodded slowly and pressed his forehead against Cas' shoulder. Cas sighed and rubbed soothing circles on Sam's back. "Did he cause it?" Sam was surprised by Cas' question and pulled back to catch his friend's concerned blue gaze. Cas tilted his head and looked at Sam knowingly. Sam pulled away completely and settled back against the wall again. Cas scooted until he was sitting beside him and glanced over at Sam expectantly.

"In a way, yeah, I think he did cause it," Sam began, "I keep seeing our Dean fading away and then that person downstairs taking his place. I try to stop our Dean from fading, but every time that I do, he fades away faster. It makes me so pissed off that I can't do anything and that I have to see...that fake version of him instead of the real one." Castiel listened silently, a troubled expression on his face. Sam brushed his hair out of his eyes and away from his sweaty forehead. It hung limply over his shoulders and was messy from sleep. 'I must look like a werewolf,' Sam thought.

"Sam, the man downstairs is Dean. He might not be the one that we know and love, but he is still here," Cas started, placing a hand on Sam's arm. Confused and angry, Sam pulled his arm out of Cas' grasp. Cas blinked in surprise and frowned a little. Sam stared at his friend in disbelief. "How could you say that?" he whispered. Cas looked at him warily, unsure of what the taller man was asking. Sam scoffed and got off of the bed, pacing. Cas scooted to the edge and sat there, watching Sam walk from one side of the room to the other. "Say what? I don't understand," he said. Sam whirled and glared at the man sitting on his bed. Cas leaned back, startled.

"How could you call him that?" Sam growled. Castiel was thoroughly confused. Sam snorted and ran a hand through his hair, turning his back to Cas. "Call him what? Dean?" Cas asked. He was beginning to feel the burning heat of anger pooling in his skin. Sam visibly flinched and turned back to Cas, eyes blazing. "His name is Dean, Sam. What else do you expect me to call him?" Cas snapped. Sam pinched the bridge of his nose and sighed angrily. Castiel stood and clenched his hands into fists. "I know that it bothers you that he looks like your brother, but we have to give him a chance. Maybe he's the key to finding our Dean," Cas said, trying to calm the man in front of him.

Suddenly, Sam snarled and grabbed Cas by the collar. "Don't you say that! Don't you dare...not you. I don't care who he looks like; he will never be Dean. You know as well as I do that there is no way to get our Dean back. You know why? Because our Dean is dead! He's gone and, no matter what you try to do, nothing can get him back!" he shouted. Castiel's eyes flashed and Sam stumbled back, cradling his jaw, with a shocked look on his face. "You punched me!" he said incredulously. Cas stood still, trembling with rage.

"You think that I don't know that my husband is dead? You think that I don't understand? It tears me up inside every time I see his face and I want to die. Sometimes I feel as though he has been put here as a punishment for me. It's like seeing a ghost and not being able to interact because you know that it isn't real. It's maddening! So, don't you dare tell me that I don't understand how you feel! The difference between us is that I am trying to put the past behind us and focusing on what we've got right now! He might not be our version, but he is still Dean Winchester and he is our friend!" Cas snarled. Shell-shocked, Sam stared at his furious friend and noticed the tears welling up in his blue eyes.

"Cas-,"

"I miss him just as much as you do,"

Sam winced at the raw emotion in Cas' voice and took a step towards him. Cas' chest heaved and he turned away from Sam. "Cas, I'm-I'm sorry," Sam whispered softly. Cas sniffled and wiped at his eyes frustratingly. Sam put a hand on Cas' shoulder and turned him around. Cas closed his eyes as Sam pulled him in for a hug. "You're right, Cas. I shouldn't have lashed out at you. You're going through the same thing I am. I should have realized that before. I'm sorry," he muttered. Cas sighed and pulled away, wiping at his eyes again. Sam awkwardly scratched at the back of his neck and watched as Cas sat back down on the edge of Sam's bed. After a few moments, Sam joined him, sitting hip to hip with his friend.

"You know, he offered to help," Cas said quietly. Sam looked at him in surprise. "Help? He did?" he asked. Castiel nodded and glanced over at the doorway. Sam followed his gaze, but all he saw was the darkness of the hallway. "Dean...said that something shoved him through that mirror. What do you think could have done it?" he said, forcing the name out through clenched teeth. Cas shut his eyes, as though pained, and licked his lips. He sighed then shook his head. "I have no idea. It could have something to do with the huntress, but I'm not sure how," he said. Sam tilted his head back and stared up at the ceiling. A knot of frustration had worked itself into his stomach and he had to clench his fists to distract himself.

Cas stood abruptly and looked down at Sam with a weary expression. "We can look more into it in the morning. I think we should accept Dean's help, too. You never know, maybe he can find something that we can't," he whispered. Sam was still doubtful, but nodded regardless. Cas smiled gently and leaned down to wrap his arms around the taller man's broad shoulders. "Goodnight, Sam. Try to have better dreams," he mumbled. Sam hugged his friend back and patted him affectionately on the back. "Goodnight, Cas. Get some rest. You need it," he said.

Cas slumped, exhausted, and shuffled out of the room with a backhanded wave. Sam chuckled a little and settled back down on his bed. He pulled the blanket up to his chin and closed his eyes, praying that he had no more night terrors. Meanwhile, downstairs lying on his back with his eyes fixated on the ceiling, lay Dean. He had heard parts of their conversation and had conflicted emotions coursing through him. He was grateful to Cas for defending him, but he was also guilt-ridden with the fact that his presence caused Sammy and Cas both so much heartbreak. As he closed his eyes, Dean vowed to use everything within his power to find a way to get this dimension's Dean back if it was the last thing he'd do.

Dean felt another tug at his heart, stronger than the one he'd had before. For some odd reason, Dean thought that it was...closer than it had been before. Shaking his head, Dean snuggled deeper into the softness of the pillow and allowed sleep to take him, his thoughts filled with the angel.

A/N: Things are starting to fall into place now. I am currently working on the next chapter, so be on the look out for another update soon! I hope you have enjoyed reading so far!