サムの大学時代の親友からメールがあり、友達のザックが殺人罪で逮捕されピンチになっているという。駆けつけるディーンとサム。ザックは殺人事件のあった時刻には遠く離れた場所にいたのに、違う場所で彼が犯行現場にいくところが監視ビデオにはっきり映っていて、証拠もばっちり残っていた。現場近くのマンホール地下で2人はシェイプシフターの変身した残骸（キモチ悪い皮みたいなもん）を発見し、テキを知るのでした。

相手は変幻自在に形を変え、別人になりすまして襲ってくるので大変です。こんなのホントにいたら怖いですよね。

サムはスタンフォード大の法学部にいたんですよね。ディーンと旅に出る直前、大学院に行くことが決まったばかりだった。というわけで彼は元々勉強好きなインテリで、一方、ディーンは悪霊狩りが仕事で趣味はポーカーとオンナというアウトロー気質。生まれは同じでも大人になってから育った環境がすごく違う。ディーンはサムの友達に初めて会って、ちょっと恥ずかしそうでした（私にはそう見えました）。こういう兄弟っていますよね。

※付録↓

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■BGM。"In-A-Gadda-Da-Vida" by Iron Butterfly, "Poison Whiskey" by Lynyrd Skynyrd, "Hey Man, Nice Shot" by Filter, "All Right Now" by Free.............................................................
■以下本エピソードから抜粋。
英語の勉強にお役立てください↓
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Sam: What are you gonna do to me?
Shapeshifter Dean: I'm not gonna do anything, Dean will, though.
Sam: You'll never catch him.
Shapeshifter Dean: Oh, it doesn't matter. Murder in the first? Of his own brother? He'll be hunted the rest of his life.
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Rebecca: What did you call it?
Shapeshifter Dean: A shapeshifter. Yeah, maybe we're crazy, but what if we're not? I mean, look, you said it yourself, that Zach was in two places at once, now tell me how that can happen?
Rebecca: Okay, so this thing, it can make itself look like anybody?
Shapeshifter Dean: That's right.
Rebecca: Well, what is it? Like a genetic freak? Shapeshifter Dean: Maybe...evolution is about mutation, right? So maybe this thing was born Human but was different, hideous and hated... until he learned to become someone else.
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Shapeshifter Dean: I must say, I will be sorry to lose this skin. Your brother's got a lot of good qualities - you should appreciate him more than you do.
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Sam: We've gotta find a phone, call the police!
Dean: You're gonna put an APB out on me?
※APB = all-points bulletin
警察無線(と訳せばよい?)
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Dean: I really wish things could be different, you know, I wish you could just be Joe College.
Sam: Nah, that's okay. You know, truth is, even at Stanford, deep down, I never really fit in.
Dean: Well, that's cuz you're a freak.
Sam: Yeah, thanks.
Dean: Well I'm a freak, too. I'm right there with you, all the way.
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(talking about the shapeshifter)
Dean: Argh, the thought of him driving my car.
Sam: Ah come on.
Dean: It's killing me!
Sam: Let it go.
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Dean: I think we're close to its lair.
Sam: Why'd you say that?
Dean: Because there's another puke-inducing pile next to your face.
Sam: Urgh, God!
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Shape-Shifter Dean: Even when we were kids, I always kicked your ass!
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Dean: You know, I gotta say, I'm sorry I'm going to miss it.
Sam: Miss what?
Dean: How many chances am I going to have to see my own funeral.
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Dean: Alright, what are we doing here at 5:30 in the morning?
Sam: I realised something - the videotape shows the killer going in but not coming out.
Dean: So he came out the back door.
Sam: Right, so there should be a trail to follow, a trail the police would never pursue.
Dean: Because they think the killer never left, they caught your friend Zach inside. (sotto voce) Still don't know what we're doing here at 5:30 in the morning.
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Sam: Hey Bec, can we take those beers now?
Rebecca: Yeah, sure.
Sam: And, ah, maybe some sandwiches too.
Rebecca: What do you think this is, Hooters?
Dean: (sotto voce) I wish.
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Dean: Sam wears women's underwear.
Sam: I've been listening, I'm just busy.
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Dean: All right, but first I want to find that handsome devil and kick the holy crap out of him!
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Dean: Man, it's not even a good picture!
Sam: It's good enough.
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Dean: That better be you Sam and not that freak of nature!
Sam: Yeah, it's me. He went to Becca's, looking like you.
Dean: Well, he's not stupid. He picked the handsome one!
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Shape-shifter Dean: 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. You don't think I had dreams of my own? But dad needed me! Where the hell were you?
Sam: Where is my brother?
Shape-shifter Dean: I am your brother! See... deep down, I'm just jealous. You've got friends. You've got a life. Me? I know I'm a freak. And sooner or later, everyone's gonna leave me.
Sam: What are you talking about?
Shape-Shifter Dean: You left. Hell, I did everything dad asked me to and he still left me! No explanation, no nothing, just poof! Left me with your sorry ass! But still, this life isn't without its perks. I mean, I meet the nicest people! Like little Becky. You know... Dean would bang her if he had the chance. Let's see what happens!
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Dean: I hate to say it but that's exactly what I'm talking about. You lie to your friends cause if they knew the real you, they'd be freaked. It's just... it'd be easier if...
Sam: ... If I was like you.
Dean: Hey man, like it or not, we are not like other people. But I'll tell you one thing. This whole gig... it ain't without perks!
(hands Sam a gun with silver bullets in it to kill the shape-shifter)
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(after Dean finds out that Sam's friend, Zach, has been put in jail for murdering his girldfriend)
Dean: Dude, what kind of people are you hanging out with?!
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Dean: Yeah, it sucks. But with a job like this you can't get close to people. Period.
Sam: You're kind of anti-social, you know that?
Dean: Yeah, you know. Whatever.
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Dean: You kidding? You still keep in touch with your college buddies?
Sam: Why not?
Dean: Well, what exactly do you tell them? You know, about where you've been? What you've been doing?
Sam: I tell them that I'm on a road trip with my big brother. I tell them I needed some time off after Jess.
Dean: Oh, so you lie to them?
Sam: No! I just don't tell them... everything.
Dean: Yeah... that's, that's called lying. Hey man, I get it. Telling them the truth is far worse!
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Dean: Man, Get that S.O.B.!
※S.O.B. = Son of a Bitch.............................................................