Wow..whoa...erm...geez...I guess that's one approach to family therapy.
From the word go, in the previews nonetheless, the message is this is gonna be an angry one. Another clue, the title, "Sex and Violence." There's definitely that.   
I didn't get to see this one live, much to my dismay. While traveling I kept looking at the clock once it approached 9pm, frowning, wondering if I could convince some bar owner in the sticks to put it on for me. The next day I downloaded the episode from iTunes and luckily I was busy at the New York Comic Con that day, for it took five hours over the slow but free wireless connection. That evening the hubby and I huddled by the laptop and watched with anticipation.
Once we picked our jaws up off the floor, we watched it again. 
This week's theme is not uncommon in the history of man. Underneath sex and violence lays mistrust, unhappiness, dissatisfaction, and restlessness. Put it in the Supernatural universe though and the results are downright explosive. Cathryn Humphries is no stranger to depicting the Winchester brotherly strife in her scripts and again she went deep and raw. Unlike her brilliant "Metamorphosis," she didn't need obvious parallels, finding the perfect antagonist to screw with needy men and bitter brothers.  
The Recap
A woman with one massive meat tenderizer prepares dinner. Uh oh, this isn't going to end well. Hubby comes home tired, and the couple is instantly sniping at each other. Considering I've been married for almost 14 years now, I call their behavior normal. Oh know she didn't! She accepted an invite from his best friend without asking?? How dare she! That's easily grounds for bashing the wife's head in with said kitchen utensil, right? I'm checking my drawers, making sure the ones I have are light and wooden. 
Birds of the Apocalypse. Yeah, that should following a marital bludgeoning. 
Dean is sleeping. Just hold that thought for a few minutes. Put the TiVo on pause, and watch. It's quite lovely. A truck goes by and he snaps awake, and surprise, Sam is not in the other bed. How many times has that happened in the series? Sam's in the bathroom on the phone. How dare he?? Good thing there are no meat pounders around. Sam comes out and Dean pretends to sleep, so he wakes him up. He wonders why Dean is puzzled that he was in the bathroom. "You want me to draw you a picture?" Sure! If it's a strange figure like the one in "Bedtime Stories," I'm interested. 
Sam's all enthusiastic about men in Iowa bashing their wives brains in. Oh Sammy, creating a diversion for your brother, humoring him while you do your thing off to the side. He's gonna be pissed when he finds out. He might try to kill you. Oh wait"¦
Anyway, this is a new one, they're pretending to be public defenders? I guess that brings Sam closer to his unrealized dream. Our meat tenderizing head basher is in orange, and pleading guilty. Sam's got his serious "you can talk to me" look, causing just about all females to melt. Dean's playing tough guy, so we're all done for by the end of this scene. Husband killed wife with full clarity, not possessed or anything. He loved her, and they were happy. Well that's a funny way of declaring love. Turns out Sam and Dean did their homework and found the guy just dropped 9,000 on a girl named Jasmine. "She was a stripper?" "Dude, her name was Jasmine." Dean's got you there Sammy.
This girl had him under some type of spell, for he killed his wife so he and Jasmine could be together forever. She disappeared after that. He doesn't know her last name, where she lives, or her real first name. He berates himself for being an idiot. Yeah, perfect self analysis there. 
Sam enters a medical clinic, and there's a doctor with a hangover. She's brunette, smart, and beautiful. Yep, Sammy's got the googly eyes. The FBI cover this week is Sam Stiles, which I've learned is the last name of the detective in Route 66. Murdock, Dean's cover, is the other name. The doctor is Cara Roberts, and she did the tox screens on the men that ganked their wives. After double checking Sammy's fake badge, accepting it to be real (man these guys are getting good at this), she reveals the strange anomaly. All three men had outrageously high levels of oxytocin. The love hormone.
This girl is offbeat and funny, managing to work in an analogy of painful tattoo removal and bad relationships while explaining oxytocin. Sam smiles as she eyes him with allure. He's hooked! Dean comes in trying to charm her, but she quickly brushes him off and goes back to eyeing Sam. Sorry, but I wouldn't be able to take my eyes off of both. Picking one would be impossible! Sam says thanks and they share another longing gaze. Oh just do it already. Then, he goes and gets cute, offering his remedy for a hangover. A greasy breakfast. Isn't that similar to the remedy that Dean gave him in "Playthings," making him barf more? "Watch it buddy, I'm the only MD here." Sam flashes one of those oh so rare gorgeous smiles. Crud, there go my hormones. 

So Dean, not happy at all, says "Dude, you totally c blocked me." Once again, the urban dictionary does not disappoint. C block is short for cock block, which by definition is "To interfere with someone who is getting acquainted with, conversing with, or hooking up with a member of the opposite sex." Uh, I'm thinking Dean tried to c block Sam, and it so didn't work. She's not your type anyway Dean. 
Dean has more info. The other two guys cleaned out their savings for their strippers, who work at the Honey Wagon, both with different looks and names. They all describe the girls as "perfect and everything they wanted." Sam makes the logical jump, a love spell is involved. Dean's too happy to care, for after how many years of cases, they finally get one involving strippers. 
Cue a rockin' White Zombie tune, a strip club, and plenty of naked girls, and Dean seems too busy playing the FBI part to gaze at these beauties. The owner thinks the murders are weird, but considering he runs a don't-ask-don't-tell type operation, it's not his problem. Sam isn't getting into the strippers either. Come on guys, you're young, and you're certainly not dead. Then again, whores aren't Sam's type, but there's no excuse for Dean. 
He gives the names of the "exotic dancers" (the owner clarifying that's what they're called), and they haven't figured out they're Disney princess names yet? Sam spouts off the latest theory from Bobby, a siren. Dean then pulls a Homer's Odyssey reference. I'm sure Cathryn Humphries got tired of all the "Dean is dumb" gripes. They are spouting their siren song. Dean rattles off two, "Welcome To The Jungle" or "Cherry Pie." I can't come up with a better one than the latter. When that song comes to mind, I think of skanks. I'm also embarrassed to admit I'm part of the generation associated with that low point in music history. Stupid being born at the wrong time. 
Sam explains the song is a metaphor. They have an allure about them, something that zombies guys out. Like maybe a doctor who hits on you the moment she lays eyes on you Sam? He even uses the old tale of sailors chasing them and crashing their ships into rocky shores. Sam gets the line of the night! "If you were a siren in 09 looking to ruin a bunch of morons, where would you setup shop?" I'd watch the moron talk Sammy. Ah well, he'll find out later.
Dean's getting it. "Whatever floats your boat, that's what they look like?" Sam says yes, and explains that sirens can read minds, see what you want most and then cloak themselves. So they are dealing with one person, and it could be anyone. They also don't know how to kill it. 
So, while they're trying to find the siren, a beautiful girl is seen hitting on a loser. One that's hung up on his mother. His sick mother.  They go to his house and she services him on the couch. Oh, but we see the true form in the mirror. That is one hideous looking creature. She tells loser to bash his mother's brains in, and luckily a fire poker is nearby that will do the trick. She leaves as the deed is being done. I'm sure he's feeling pretty foolish, especially considering how ugly she really is.

Sam's state of the art blackberry is on the table, and Dean gazes at it with trepidation. Okay, not that much since he picks it up and dials the mysterious number that's been the source of Sam's secret calls. It's Ruby, saying "Hey Sam!" Yeah, not what Dean wanted to hear. Needless to say, he's borderline crushed.  He needs a hug.  He hangs up just as Sam walks in. He was apparently looking into the latest murder. He left his cell behind? That's pretty careless, especially when you want to hide something from your brother.
This reminds of an anecdote I got this weekend during the New York Comic Con. In Joss Whedon's panel, he brought up how he was asked about Dollhouse how they could make all these mistakes. He said if they didn't, there would be no show.  He equated it to all those people getting murdered around Angela Lansbury.  So, I'm forgiving the leaving the cell behind and not checking if Nick Monroe was legit just because of that. As a matter of fact, I forgive all their stupid mistakes now. 
Bobby calls, and once Sam shows off his cool speakerphone feature (hmm, the product placement is getting really stretched, isn't it?) Bobby finds a way to kill the siren. "You need a bronze dagger covered in the blood of a sailor under the spell of the song." Ha, good luck with that one! Oh wait, Bobby eventually figures it out because he's awesome. The siren is using a toxin or venom. If she gets a dose of her own medicine, it'll come back to bite her. The victims don't have the toxin anymore, so they don't know where to get the blood. Sam knows where. He gets to visit his lady friend again.
They get there and she only acknowledges Sam, smiling away. Sam blushes back, and then gets to the point, but not before Dean gives him a jealous look. Oh come on Dean, that ship has sailed. Dean asks for the samples just as another well dressed man shows up. He's got an FBI badge too, direct from the Omaha office. The name is Nick Monroe. Sam and Dean don't flinch, saying they're from DC and Sam even has the number for their Assistant Director. He does what any good Fed would do, he calls. 
On the other line is Bobby, pulling the whole "we have jurisdiction" crap when cooking a burger and wearing a "kiss the cook" apron. Nick buys it, and Bobby hangs up the phone in the slot marked "FBI." It's there with four other phones marked "Health Dept.," "Police," "Fed. Marshall," and "C.O.C." His words as hanging up are "those idgits." Ha! They brought back his pet name for the boys. 

Nick apologizes, gives his theory about the stripper, and Dean is ready to pull the lone wolf thing when Sam takes him aside. Sam suggests he take Nick to the club. Sam wants to stay behind and "get the blood samples." That's definitely a new phrase for "bang the lady doctor." Dean agrees reluctantly, stating he's doing it "for the girls." Nice try Dean, but Sam knows you too well. 
Dean and Nick go out to the car, and Nick has huge Impala envy. Yep, that's the perfect way to score points with Dean. Back to Sam falling over lady doctor, and they find the samples are gone. Back to Dean and Nick, both acting like the responsible Feds they're supposed to be by slamming shots, watching the strippers, excuse me, exotic dancers, and talking Led Zeppelin. They're BFFs already! Nick has found something that Sam and Dean didn't. Hyacinths petals left at the crime scenes. Dean knows where that came from.
Back to the doctor's office, where the hyacinths are in a vase, and she and Sam are having no luck with the security tapes. They must have been tampered with. Sam admits he wants the blood because he thinks someone drugged the men. So, lovely Cara decides this is the right time to pull out some whiskey and seduce the tall and very handsome FBI agent.  
So, she starts by asking, "Haven't you ever been in a relationship where you really love someone and still kind of wanted to bash their head in?" What, you mean like a brother that you're on the road with 24/7? Sam guesses she knows this from experience. So, while Sam feels guilty for prying, she pulls out the whiskey. Now he's even more surprised. The way these two have gone back in forth in their scenes is quite well done.  They've got all the little flirting and attraction mannerisms down where they aren't overdone and deliver some great chemistry. 
She gets real cutesy on him, handing him the drink and saying with feigned seriousness, "It's medicine. I'm a doctor." Sam eats it up and takes the drink. She pours her heart out about her ex-husband Carl, and Sam kicks into that empathetic listener mode that no girl can resist. During their tender moment Sam's cell phone goes off, he checks it, and ignores it. Hmm, must be Dean. She pours another drink, goes into this whole "Have fun, no regrets, and live like there's no tomorrow," speech. 
Now that she's reeled him in, she whispers in Sam's ear about how she's been thinking about parts of him, like his lips, and rips off his tie. Sam lets her do all this with a smile on his face. She kisses him gently, and suddenly they're ripping off shirts next. He slams her against the window (for we know that's a patented Sam sex move), and the shot moves off their nakedness to the hyacinths on the desk. Um, has Sammy been sirened? 
Next scene Sam walks down the long, red hallway. That's not the first time a red room has been used this season in that way. It was there in the bathroom for Dean's memory of Hell in "Lazarus Rising," the hallway at Bobby's place in "Are You There God: It's Dean Winchester," and the scenes with imagined yellow-eyed Sam and Lilith in "Yellow Fever." It's either a symbol, or the producers are having tons of fun with us. I like seeing it back. 
NOW Sam decides to call Dean, who's freaking out. Sam tells him he was with Cara, and now Dean is convinced Sam's been infected by the siren. Sam's unconvincing denial when Dean asks if he slept with her is probably the clue. "The middle of Basic Instinct and you bang Sharon Stone?" Why not? She's a hot chick too. So what if she was evil? 
Sam's hunch is it isn't her. Dean gives what he perceives to be hard facts. Nick found hyacinths at the crime scene, like the ones in Cara's office. Plus, she's only been in town two months, when the murders happened, and her husband dropped dead mysteriously of a heart attack. Sam still doesn't think it's her, and is rolling his eyes at Dean's accusations. Then Dean wants to say something and backs off, but now Sam is angry and challenges him to say it. Okay, remember Sam, you asked. "First it's Madison, then Ruby, and now Cara. What is with you and banging monsters?" Ouch! Low blow Dean! 
Sam adamantly tells Dean he's fine. Dean doesn't believe it. "You don't trust me?" Sam asks. "No." Dean says. Sam asks him to meet him somewhere and they'll figure things out. Dean again says no, and tells him he's gotta handle this by himself before hanging up. Sam hangs up the phone and chucks it across the room. The shot here on Sam is very interesting since its showing his image in the mirror. He walks up to the mirror, and has the most frightening glare of fury in his eyes. I was expecting him to go all Incredible Hulk next. What ever you do, don't make Sammy angry. You won't like him when he's angry. 
Dean calls Bobby, leaves a message he thinks Sam is in trouble. That's likely why Bobby shows up later. Then he calls Nick, asking him to tail the doctor. She's seen next going into a bar. What, sex with Sam wasn't enough for one evening? Either he didn't leave that great an impression, or she's got a sex addiction. Dean gets in the car with Nick, and Nick calls Dean's theory of how this is all being done by one woman "crazy on toast." Dean says he has his reasons and he's gonna have to trust him on that one. Nick says okay and Dean is floored. "Thank you, that's actually nice to hear." Uh oh, is that a sign of brotherly tension?   
Dean pulls out his flask, takes a drink of whisky, and hands it to Nick. Nick laughs, for as we're about to find out, Dean is making this too easy. He drinks, and hands it back to Dean, who takes another swig. So, Nick pitches "how is she drugging them" theories. Dean suspects injecting them or through physical contact. Uh, like saliva? Nick gives Dean a huge "gotcha" by telling him he should have wiped that bottle before drinking. Now he has Dean under his control.
The plan is easy. Get rid of Sam. Dean goes along with it without argument. Oh Dean, your ideal person to be with isn't a gorgeous stripper, but the ideal brother? Ouch! Things are definitely not looking good for Sam right now. It only gets worse when Sam arrives at the motel room and Dean grabs him from behind and puts a knife to his throat. 
Sam quickly figures out what's going on, the siren in Nick. He tries to get Dean to snap out of it, but Dean follows Nick's orders to slice Sam on the neck. Nick can't help but gloat. "I gave him what he wanted, and it wasn't some bitch in a g-string. It was you. A little brother that looked up to him." Sam sneers at the diabolical plan. Uh Sam, I would be more offended right now than anything. 
Nick admits watching someone kill for you is the best feeling in the world. He also gets bored and likes falling in love, again and again. Yep, psycho siren alright. Sam calls him a needy pathetic loser, which might not be the thing to say when the villain has the ability to infect you on the spot. He pries open Sam's mouth and sprays his special toxic spit. Gross! Sam's look changes from defiance to pure evil, and let the showdown begin! 
Dean follows instructions to let Sam go, and Sam steps away then turns around. Nick tells them they have some things to get off their chests (boy do they!) and whoever survives gets to be with him forever. Sam and Dean both stare at each other in super pissed off mode. You know, I'm just gonna let the words speak for themselves here. 
Dean: Well I don't know when it happened, maybe when I was in Hell, maybe when I was staring right at you. The Sam I knew, he's gone.
Sam: That so? 
Dean: It's not the demon blood, or the psychic crap. It's the little stuff, the lies, the secrets.
Sam: Yeah, what secrets?
Dean: The phone calls to Ruby for one.
Sam: So I need your say so to make a phone call?
Dean: That's the point. You're hiding things from me. What else aren't you telling me?
Sam: None of your business.
Dean: See what I mean? We used to be in this together. We used to have each other's backs.
Sam: Okay, fine. You want to know why I didn't tell you about Ruby? And how we're hunting down Lilith? Because you're too weak to go after her Dean. You're holding me back. I'm a better hunter than you are, stronger, smarter. I can take out demons you're too scared to go near.
Dean: That's crap.
Sam: You're too busy sitting around feeling sorry for yourself. Whining about all the souls you tortured in Hell. Boo hoo.

That really sets Dean off, and he throws the knife at Sam, who swerves to miss it. Sam punches, Dean punches, and it goes back and forth for a while until Sam tosses Dean through the traditional tacky motel room divider that's a trademark for the series. He pins Dean against the wall. "You're not standing in my way anymore." He pounds on Dean some more, but then Dean throws him off, rears up, and then charges at him. He and Sam go crashing through the door. 
That's enough to knock the wind completely out of Sam, and he struggles on the floor while Dean goes for a nearby axe. How convenient one of those happened to be there. "Tell me again how weak I am Sam. How I hold you back." Dean throws a cold stare of pure evil before raising the axe, while a worried Sam on the ground realizes he's a goner. Sam braces for the blow as Dean swings the axe down.
Oh, but it's blocked! By Bobby! Bobby swiftly stabs Dean in the arm with a bronze dagger, and then throws it with a perfect strike into Nick's back as he's running away. Nick dies and Sam and Dean snap out of it. They look at each other horrified, the realization as to what they almost did hitting them hard. They do care about each other!
Time for another Impala confessional moment. I really don't mind these if the Impala looks scenic enough. Here, it does. They're under a bridge, Bobby's beat up Chevelle is there, and Bobby gives them two sodas. "You boys are driving, ain't ya?" I do love this new sober Bobby. 
Sam looks pretty mortified, while Dean looks uncomfortable. Sam thanks Bobby, and Bobby says they would have done the same for him. He then tells them this all could have been avoided if they had picked up a phone and discovered Agent Nick Monroe wasn't real. Yeah, but then the episode would have ended halfway through and we wouldn't have gotten that cool fight scene. Joss Whedon is a genius. 
Bobby asks if they're going to be okay, and they both casually lie and insist yes. Bobby goes to leave, but as the perfect father figure offers consolation first. "You know those sirens are nasty things. That it got to you, that's no reason to feel bad." That offers very little consolation and Bobby drives off. 
Dean asks Sam if he was going to say goodbye to Cara. Sam isn't interested, and doesn't see the point. Dean's shocked that Sam is going to "love "˜em and leave "˜em." Sam apologizes to Dean, telling him he didn't mean those things and it was just the spell talking. Dean gives a quick and uncomfortable "me too." Sam asks with his very sad puppy dog eyes, "So, we're good?" "Yeah, we're good." You are SO not good. Sam meekly nods, Dean nods, and then they get in the Impala. 
I've watched that last scene about a million times trying to interpret it, and here's my take. Sam feels really bad, more embarrassed than anything. Dean is just plain hurt and doesn't want to talk about it. Siren spell or not, Sam lied. Dean's not forgetting that. "We're good" really means "I'm not talking about it anymore." Dean's hurt though come from a sense of betrayal. He can never trust Sam again. The Sam he knew is gone and very likely dead to him now.  
That is a VERY sad ending and a setup for the rest of the season. The damage is now done and from this point forward any shred of loyalty to each other left is compromised. Of course that only intrigues me more to watch, but I'm stocking up heavily on Kleenexes from here on out. 
I give this one a grade of an A, but then again, Cathryn Humphries is one of the most consistent writers on the team, especially when exposing the core of the brotherly issues. Again I leave extremely satisfied. The rest of this season is going to be explosive.