In an unassuming motel room, Sam and Dean sat opposite each other, their legs spread to create a type of cage for Mack. It was a week after the wendigo case. The young girl was standing, holding her father's fingers facing her uncle as she attempted to take her first steps. "Come on, Kinley," Sam encouraged her. "Come to Uncle Sammy." He reached out to her as she moved further away from Dean. A giant grin on her face featuring mostly gums with her front top and bottom teeth appeared as she let go of Dean's fingers and grabbed Sam's instead. "Good job!" he cried, both he and Dean grinning proudly. "Back to Dada, now."

He turned her, holding her hands the same way Dean had as she made her way back to her father. "Da da da," she grinned, toddling her way across the space toward him. "That's it. Come here, bug," he encouraged her. He scooped her up when she was close enough, tossing her in the air and making her laugh. "Good job, baby girl," he grinned, kissing her on the cheek. "Dada loves you so much."

A month later, the Impala pulled into a gas station. Sam was distracted looking at his PalmPilot. "Alright, I figure we'd hit Tucumcari by lunch, then head south, hit Bisbee by midnight," Dean said. Sam didn't respond. "Sam wears women's underwear." Sam spoke without looking up. "I've been listenin', I'm just busy." Dean raised his eyebrows. "Busy doin' what?"

"Reading emails."

Dean got out of the car, starting to fill up the tank. "Emails from who?" he pressed. "From my friends at Stanford," Sam answered. "You're kidding. You still keep in touch with your college buddies?" Sam finally looked up from the PalmPilot. "Why not?" he asked. "Well, what exactly do you tell 'em?" Dean queried. "You know, about where you've been, what you've been doin'?"

"I tell 'em I'm on a road trip with my big brother and my niece. I tell 'em I needed some time off after Jess," Sam informed him. "Oh, so you lie to 'em," Dean translated. "No. I just don't tell 'em... everything." Dean scoffed. "Yeah, that's called lying. I mean, hey, man, I get it, tellin' the truth is far worse." Sam glared out at Dean. "So, what am I supposed to do, just cut everybody out of my life?" Dean shrugged. "You're serious?"

"Look, it sucks, but in a job like this, you can't get close to people, period."

"You're kind of anti-social, you know that?"

"Yeah, whatever." Dean got into the back seat, unbuckling Mack and grabbing her diaper bag. "God..." Sam breathed. "What?" Dean asked him, pausing. "In this email from this girl, Rebecca Warren, one of those friends of mine." Dean smirked. "Is she hot?" Sam ignored him. "I went to school with her, and her brother, Zack. She says Zack's been charged with murder. He's been arrested for killing his girlfriend. Rebecca says he didn't do it, but it sounds like the cops have a pretty good case."

"Dude, what kind of people are you hangin' out with?" Dean raised his eyebrows. "No, man, I know Zack," Sam said, shaking his head. "He's no killer." Dean frowned. "Well, maybe you know Zach as well as he knows you."

"They're in St. Louis. We're goin'." Dean chuckled, adjusting the strap of the diaper bag on his shoulder. "Look, sorry 'bout your buddy, okay? But this does not sound like our kind of problem." Sam was insistent. "It is our problem. They're my friends."

"St. Louis is four hundred miles behind us, Sam." The brothers glared at each other for a minute and Dean sighed. "Give me a minute to change Mack and we'll head out. Watch the pump." He headed into the gas station with Mack.

"Oh my God, Sam!" Rebecca cried happily when she answered the door. "Well, if it isn't little Becky," Sam replied, grinning back. "You know what you can do with that little Becky crap." She smiled and they hugged. Dean fidgeted nervously behind Sam, Mack strapped into the hiking backpack on his back. "I got your email," Sam told her when they pulled apart. "I didn't think that you would come here," Rebecca shook her head. Dean stepped forward, extending his hand. "Dean. Older brother."

Rebecca shook his hand, glancing over his shoulder at Mack. "And who's this little cutie?" she asked. "Mack. My daughter." Rebecca waved at Mack. "Hello," she grinned at her. "Hi," Mack replied, waving back over Dean's shoulder. "We're here to help," Sam informed Rebecca. "Whatever we can do." Rebecca smiled, nodding. "Come in." They walked inside the house and Dean shut the door. "Nice place."

"It's my parents'," Rebecca informed Dean. "I was just crashing here for the long weekend when everything happened. I decided to take the semester off. I'm gonna stay until Zack's free." Dean nodded in acknowledgement, glancing around the house. "Where are your folks?" Sam asked. "They live in Paris half the year, so they're on their way home for the trial," Rebecca replied, leading the way into the kitchen. "Do you guys want a beer or something?"

Dean smiled, taking the backpack with Mack in it off his back and setting it down next to him on the ground. "Hey-" Sam cut him off. "No, thanks. So, tell us what happened." Dean glared over at his brother as Rebecca launched into an explanation. "Well, um, Zack came home, and he found Emily tied to a chair. And she was beaten and bloody, and she wasn't breathing." She started to cry. "Uh oh!" Mack cried. Dean didn't acknowledge it right away as Rebecca continued. "So, he called 911, and the police- they showed up, and they arrested him. But, the thing is, the only way Zack could've killed Emily is if he was in two places at once."

"Uh oh, dada!" Mack cried again. He tore his gaze from Rebecca, looking around until he spotted the rabbit she'd dropped while Rebecca finished her story. "The police- they have a video. It's from the security tape across the street. And it shows Zack coming home around 10:30. Now, Emily was killed just after that, but I swear, he was here with me, having a few beers until at least after midnight."

"You know, maybe we could see the crime scene. Zack's house," Sam suggested. "We could?" Dean asked, looking over at his brother skeptically. "Why?" Rebecca chimed in. "I mean, what could you do?" Sam shrugged. "Well, me, not much. But Dean's a cop." Dean laughed. "Detective, actually," he corrected, going with Sam's lie. "Really?" Rebecca eyed him and he nodded. "Where?"

"Bisbee, Arizona. But I'm off-duty now."

"Bit! Bit!" Mack cried, reaching for the rabbit Dean still hadn't given back to her. "You guys, it's a nice offer, but I just- I don't know," Rebecca hesitated. "Bec, look," Sam sighed, "I know Zack didn't do this. Now, we have a way to prove that he's innocent." She hesitated a second longer, then nodded. "Okay. I'm gonna go get the keys." She headed out of the room. "Oh, yeah, man, you're a real straight shooter with your friends," Dean shot at Sam sarcastically once she was out of earshot.

"Look, Zack and Becky need our help," Sam pointed out. "I just don't think this is our kind of problem," Dean said. "Two places at once? We've looked into less." Dean didn't respond, defeated.

After checking out Zack's house and learning that the neighbor's dog went psycho right around the time Zack's girlfriend was killed, they headed back to Rebecca's parents' house so they could watch the security footage she had swiped off the lawyer's desk. "Here he comes," Rebecca said. The footage showed Zack entering the house. "22:04, that's just after ten," Dean acknowledged the time stamp. "You said time of death was around 10:30." Rebecca nodded. "Our lawyers hired some kind of video expert. He says the tape's authentic. It wasn't tampered with." Sam noticed something on the tape.

"Hey, Bec, can we take those beers now?" he asked. "Oh, sure." She got up to go to the kitchen. "Hey," Sam called her back. "Maybe some sandwiches, too?" Rebecca laughed. "What do you think this is, Hooters?" She left the room. "I wish," Dean muttered. "What is it?"

"Check this out."

Sam rewinded the tape, replaying it. One of the frames showed Zack looking directly into the camera, his eyes silver. Sam paused the footage on the frame. "Well, maybe it's just a camera flare," Dean suggested. "That's not like any camera flare I've ever seen. You know, a lot of cultures believe a photograph can catch a glimpse of the soul."

"Right."

Dean looked down at Mack, who was curled into his side with her rabbit clutched in one arm and her thumb in her mouth. She was fighting to stay awake, blinking sleepily. He started running his fingers through her hair, coaxing her further asleep. "Remember that dog that was freakin' out?" Sam asked. "Maybe he saw this thing. Maybe this is some kind of dark double of Zack's, something that looks like him but isn't him." Dean nodded. "Like a Doppelganger."

"Yeah. It'd sure explain how he was two places at once."

"Alright, so what are we doing here at 5:30 in the morning?" Dean asked. Sam had dragged him out of bed and driven them over to Zack's house. "I realized something. The videotape shows the killer goin' in, but not comin' out," Sam answered. "So, he came out the back door?" Dean yawned, leaning against the car with Mack sleeping in his arms. "Right. So, there should be a trail to follow. A trail the police would never pursue." Dean nodded. "'Cause they think the killer never left. And they caught your friend Zack inside. I still don't know what we're doing here at 5:30 in the morning."

Sam moved a little ways away, looking around, and noticed blood smeared on a nearby telephone pole. "Blood. Somebody came this way." Dean headed over with Mack still in his arms, taking a look himself. "Yeah, but the trail ends," he pointed out. "I don't see anything over here." Just then, an ambulance drove past them with its lights and sirens blaring. Mack stirred in Dean's arms as the brothers exchanged a look. Dean soothed her back down as they went to investigate.

They joined a crowd across the street from a house where some police officers were putting an Asian man in the back of one of the police cars with cuffs on. "What happened?" Dean asked one of the women in the crowd. "He tried to kill his wife. Tied her up and beat her," she replied. "Really?" Sam raised his eyebrows. "I used to see him going to work in the morning," the woman continued. "He'd wave, say hello. He seemed like such a nice guy."

Sam poked around while Dean continued asking around for more information. When he headed to find Sam and let him know what he'd found out, he had Mack on his back strapped into the hiking backpack. "Hey." Sam turned to face him. "Remember when I said this wasn't our kind of problem?" Sam nodded. "Yeah."

"Definitely our kind of problem."

"What'd you find out?" Sam queried. "Well, I just talked to the patrolman who was first on the scene, heard this guy, Alex's story. Apparently the dude was driving home from a business trip when his wife was attacked." Sam frowned. "So, he was two places at once." Just like Zack. "Exactly," Dean said. "Then he sees himself in the house, police think he's a nutjob."

"Two dark doubles attacking loved ones in exactly the same way," Sam mused. "Could be the same thing doin' it, too," Dean added. Sam was quiet, thinking for a moment. "Shapeshifter?" he suggested. "Something that can make itself look like anyone?" Dean shrugged. "Every culture in the world has shapeshifter lore. You know, legends of creatures who can transform themselves into animals or other men."

"Right, skinwalkers, werewolves," Sam nodded. "We've got two attacks within blocks of each other. I'm guessin' we've got a shapeshifter prowlin' the neighborhood," Dean said. "Let me ask you this- in all this shapeshifter lore, can any of them fly?" Dean shook his head. "Not that I know of." The younger Winchester frowned. "I picked up a trail here. Someone ran out the back of this building and headed off this way."

"Just like your friend's house."

"Yeah. And just like at Zack's house, the trail suddenly ends. I mean, whatever it is just disappeared." Dean hummed curiously. "Well, there's one other way to go- down." They both looked down in unison, spotting a manhole. They got the lid off, climbing down the ladder into the sewer and looking around. "I bet you this runs right by Zack's house, too," Sam said. "The shapeshifter could be using the sewer system to get around." Dean crouched down, spotting something by the wall. "I think you're right. Look at this."

Sam crouched down beside him, looking at the pile of blood and skin he'd found. "Is this from his victims?" Sam asked. Dean took out his pocket knife, using it to hold up some of the skin. "You know, I just had a sick thought. When the shapeshifter changes shape- maybe it sheds." Sam wrinkled his nose, looking just as disgusted as Dean. "That is sick," he said. They headed back up to the surface, going back to the Impala.

While Dean got weapons ready, Sam got a call from Rebecca telling him she didn't need their help anymore. She had found out that Dean wasn't really a detective and said that them visiting the crime scene could have ruined Zack's case. They headed back down into the sewer, and ran into the shifter, but it got away before they could kill it. When they got up to the surface, night had fallen.

"Alright, let's split up," Sam suggested. "Alright, I'll meet you on the other side." Sam went off in one direction, concealing his gun in his jacket, while Dean went the other way, keeping his gun out. He'd left Mack back at the Impala, figuring it wouldn't take long to return to her. Sam was waiting on the other side of the building on a street corner when Dean came up behind him. "Hey," Dean called out. Sam turned to face him. "Anything?"

"No. He's gone."

"Alright. Let's get back to the car." Sam headed across the street toward the car ahead of Dean. "You think he found another way underground?" Sam asked. "Yeah, probably," Dean replied. "You got the keys?" Sam stopped, glancing in the backseat at Mack as he thought. He turned back toward Dean. "Hey, didn't Dad stop a shapeshifter in San Antonio."

"Oh, that was Austin. It turned out not to be a shapeshifter, it was a thought form. A psychic projection, remember." Sam nodded. "Oh, right. Here ya go." He threw the keys to Dean and moved away, checking on Mack. She was sleeping soundly in her car seat. He took out his gun then, pointing it at Dean- the shapeshifter. "Don't move!" he ordered. The shifter turned to face him. "What have you done with him?"

"Dude, chill," the shifter said. "It's me, alright?" Sam shook his head. "No, I don't think so. Where's my brother?" The shifter kept up the façade, not backing down. "You're about to shoot him. Sam, calm down." Sam glared at the shifter. "You caught those keys with your left. Your shoulder was hurt." The shifter scoffed. "Yeah, it's better. What do you want me to do, cry?"

"You're not my brother."

"Why don't you pull the trigger, then?" the shifter challenged, lowering his voice. "Hm? 'Cause you're not sure. Dude, you know me." He reached into the arsenal for a weapon. "Don't," Sam said. The shifter paused, then hit Sam with a crowbar, knocking him out.

Sam came to in a dingy, dusty room. His neck and hands were bound to a wooden post. As he looked around, he spotted Mack in her car seat off to the side. The shifter came over then, backhanding him across the face. Sam groaned. "Where is he? Where's Dean?" Sam asked. "I wouldn't worry about him. I'd worry about you," the shifter smirked. "Where is he?" Sam repeated. "You don't really wanna know." The shifter chuckled. "I swear, the more I learn about you and your family- I thought I came from a bad background."

Over in her car seat, Mack made a noise as she began to stir. The shifter looked over at her, grinning. "Don't," Sam said. "Leave her alone." The shifter ignored him, heading over and crouching down to unstrap Mack from the car seat. "Da da," she said as he gathered her in his arms. "Hey, bug," he murmured, then looked back over at Sam. "Let her go," Sam told him. "'Ammy?" Mack asked, seeing him.

He struggled against the ropes, jaw clenched. "Uncle Sammy's just fine, bug," the shifter told her. "Here. Play with your rabbit for a minute, okay?" He set her down on the floor, taking her rabbit out of the diaper bag and giving it to her. "What do you mean, learn?" Sam asked, trying to get the shifter's attention back off of Mack. The shifter clutched his head almost painfully, then relaxed again, staring at Sam. "He's sure got issues with you. You got to go to college. He had to stay home. I mean, I had to stay home. With Dad. Only good thing that happened during that time was getting my daughter. You don't think I had dreams of my own? But Dad needed me. Where the hell were you?"

"Where is my brother?" Sam asked again. The shapeshifter leaned in close to him, smirking. "I am your brother. See, deep down, I'm just jealous. You got friends. You could have a life. Me? I know I'm a freak. And sooner or later, everybody's gonna leave me." He backed off. "What are you talking about?" Sam pressed. "You left. Hell, I did everything Dad asked me to, and he ditched me, too. No explanation, nothin', just poof. Left me with your sorry ass and a daughter to raise. And it's not like I can give her a life she deserves. Not as long as we're still hunting. But still, this life? It's not without other perks."

The shifter laughed. "I meet the nicest people. Like little Becky. You know, Dean would bang her if he had the chance. Let's see what happens." He smiled, throwing a sheet over Sam. He headed over to where Mack was waiting. "Hey, bug. Wanna go for a drive?" He picked her up, strapping her back in the car seat and heading out the door. Sam struggled, managing to get the sheet off of him. "Damn it," he muttered when he wasn't able to get out of his restraints. There was a cough in another area of the room.

"That better be you, Sam, and not that freak of nature," Dean's voice met his ears. Sam laughed. "Yeah, it's me. He went to Rebecca's looking like you. And he took Kinley with him."

Mack was on the floor of Rebecca's living room playing with toys while Rebecca and the shifter talked on the couch in front of the fireplace. "So, you're saying that there's something out there that made itself look like my brother," Rebecca said. "Mmhmm," the shifter nodded. "What'd you call it?" she asked. "A shapeshifter." Rebecca laughed, rolling her eyes. "Yeah, maybe we're crazy. But what if we're not? I mean, look, you said it yourself that Zack was in two places at once. Now, tell me how that can happen."

"Okay, so this thing- it can make itself look like anybody?" The shifter nodded. "That's right." Rebecca laughed again, looking over at Mack. She'd gotten bored of her toys and had pulled herself up on the coffee table, getting distracted by some magazines and other items Rebecca had there. "Well, what is it, like a genetic freak?" Rebecca looked back at the shifter, who laughed. "Maybe. Evolution is about mutation, right? So maybe this thing was born human but was different. Hideous and hated. Until he learned to become something else."

Rebecca shifted uncomfortably, looking around the room again. Unnoticed by her, the shifter's eyes glinted silver and he smiled. "It's funny. I kinda understand him. He's all alone- close to no one. All he wants is for someone to love him. He's like me." Rebecca continued to squirm in her spot as the shifter continued. "You know, everybody needs a little human touch now and then. It's so hard to be different." He reached forward, tucking Rebecca's hair behind her ear. She shrugged away, putting more space between them on the couch.

"You should go," she told him. He leaned in, whispering something in her ear. She stared at him, horrified, and stood up. "You are disgusting, just get the hell out of here!"

"Rebecca, just calm down." The shifter stood up. "Calm down? What is wrong with you? Just take your daughter and go." The shifter glared at her. "What's wrong with me? What's wrong with you?" Rebecca walked over to the phone. "I'm calling the police." The shifter walked over, taking the phone away and tossing it to the floor. Rebecca screamed and tried to run away. The shifter tripped her, causing her to fall to the ground. He straddled her legs, beginning to tie her hands with the telephone cord. "Give me your hands! Shut up!"

Sam and Dean headed down an alley, keeping out of sight after watching a news report about how the shifter had attacked Rebecca. "Come on," Sam told Dean, then paused. "They said attempted murder. At least we know-"

"I didn't kill her," Dean finished. "We'll check with Rebecca in the morning, see if she's alright." Dean nodded. "Alright, but first I wanna find that handsome devil and kick the holy crap out of him." Sam gave him a look. "We have no weapons. No silver bullets." Dean glared back. "Sam, the guy's walkin' around with my face, okay. And he has my daughter. It's a little personal, I wanna find him." Sam sighed. "Okay. Where do we look?"

"Well, we could start with the sewers."

"We have no weapons," Sam pointed out again. "He stole our guns, we need more." They were both quiet, thinking. "The car?" Sam suggested. Dean nodded. "I'm bettin' he drove over to Rebecca's." Sam nodded as well. "The news said he fled on foot. I bet it's still parked there." Dean made a face. "The thought of him drivin' my car." Sam rolled his eyes. "Alright, come on." They started walking down the alley again. "It's killin' me," Dean whined. "Let it go!"

They continued to stick to alleyways and other hiding spots all the way over to Rebecca's. When they arrived, the Impala was still parked outside the house. "Oh, there she is," Dean breathed a sigh of relief. "Finally, something went right tonight." Just then, a police car pulled up and parked next to the Impala. "Oh, crap." They turned, finding another police car parked a few yards away. "This way, this way." Dean moved toward a nearby fence.

"You go. I'll hold 'em off," Sam told him. "What are you talkin' about? They'll catch you," Dean said. "Look, they can't hold me. Just go, keep out of sight. Meet me at Rebecca's." Dean turned, starting to climb over the fence. "Dean!" Sam called. The elder Winchester turned back one more time. "Stay out of the sewers alone." Dean didn't respond, returning to his task of climbing the fence. "I mean it!" Sam yelled.

"Yeah, yeah!" Dean called back. "Don't move! Keep your hands where I can see 'em!" one of the police officers told Sam. He raised his hands in the air, allowing the officers to take him away. Dean stayed hidden out of sight until they were gone, and then circled back to the car. "I'm sorry, Sam, but you know me- I just can't wait," he muttered to himself, closing the trunk after getting a gun and some more silver bullets. He headed over to the nearest manhole, climbing down into the sewer to look around.

As he was wandering, he came across a chamber filled with candles and chains. Revolting piles of blood and skin were on the floor. He heard a noise, heading to another area of the sewer. There was a figure covered in a sheet like he and Sam had been after the shifter attacked them. When he took the sheet away, he found it was Rebecca, her hands and feet bound with rope. "Rebecca?" he asked. He started untying the ropes. "What happened?"

"I was walking home, and everything just went white," she cried. "Someone hit me over the head, and I wound up here just in time to see that thing turn into me. I don't know, how is that even possible?" Dean swallowed, a sinking feeling in his chest. "Okay, okay. It's okay." He finished untying her, helping her to her feet. "Come on. Can you walk?" She nodded. "Okay, we've gotta hurry. Sam went to see you."

The shapeshifter had changed from Rebecca back into Dean, tying Sam up in Rebecca's living room. In the other room, they could hear Mack crying. "What are you gonna do to us?" Sam asked. "Oh, I'm not gonna do anything. Dean will, though," the shifter replied with a smirk. "They'll never catch him." The shifter chuckled. "Oh, it doesn't matter. Murder of the first of his own brother and kid? He'll be hunted for the rest of his life." He picked up a sharp knife, examining it. "Shall we get the little bug and have her join the party?"

"No! Don't!" The shifter ignored Sam, setting the knife down temporarily to go get Mack from the other room. Sam struggled against his restraints as the shifter returned with Mack in her car seat. She was still screaming loudly as he set her down on the floor across from Sam and went to the kitchen again. He rummaged through the cupboards, coming back with a glass and some whiskey.

"I must say, I will be sorry to lose this skin," he lamented. "Your brother's got a lot of good qualities. You should appreciate him more than you do." Sam continued to struggle against his restraints as the shifter poured himself a drink. "Cheers." He downed the whiskey, then picked up the knife and stuck it into the edge of the pool table. Sam lifted his legs, kicking the shifter, who fell to the ground. He used the knife to cut the ropes from his hands, then grabbed it and swung at the shifter when he got up. The shifter grabbed his arm in mid-swing and twisted it, making him fall to the ground.

"Oh, you son of a bitch," the shifter growled. They continued to fight as Mack continued screaming in her car seat. Sam tried to pin him down, but failed. "Not bad, little brother." Sam clenched his jaw angrily. "You're not him." They continued to fight, the shifter throwing Sam against the bookshelf. It fell apart, books raining down on Sam. "Even when we were kids, I always kicked your ass." The shifter grabbed a pool cue and swung at Sam, missing and hitting a light fixture instead.

They ended up back in the living room, breaking the coffee table as they fell onto it and rolled onto the floor. The shifter managed to pin Sam to the floor, starting to choke him. "Hey!" the real Dean yelled. The shifter got off Sam, turning to face him. Dean shot his gun twice, hitting the shifter in the heart. "Sam!" Rebecca cried, rushing over to him. Dean took his necklace back from the shifter, then hurried over to get Mack out of her car seat, cradling her close.

The next morning, after saying goodbye to Rebecca, the Winchesters headed out of town. "Sorry, man," Dean apologized. "About what?" Sam asked. "I really wish things could be different, you know? I wish you could just be... Joe College."

"No, that's okay. You know, the truth is, even at Stanford, deep down, I never really fit in."

"Well, that's 'cause you're a freak," Dean joked. "Yeah, thanks," Sam scoffed, rolling his eyes. "Well, I'm a freak, too. I'm right there with ya, all the way." Sam laughed as Dean glanced back at Mack in the rearview mirror. She was rubbing her rabbit's ear with one hand and sucking her thumb with the other, staring out the window from her car seat. "Yeah, I know you are," Sam said. "You know, I gotta say- I'm sorry I'm gonna miss it."

"Miss what?"

"How many chances am I gonna have to see my own funeral?"