In Chicago, Ennis Ross takes his girlfriend Tamara to a fancy restaurant, Il Segundo. She wonders why he brought her there and Ennis spots the matre de, Maurice, and goes over to ask him to put his engagement ring for Tam in a glass of champagne. Maurice dismissively says he will and another customer, Sal Lassiter, interrupts them. Ennis complains and Sal tells his bodyguard Marv to back off. As they talk, Ennis briefly sees Marv in a mirror and discovers that his face is hideously twisted. Maurice leads Sal and Marv off to a private club and Sal greets an old girlfriend, Mindy. When she says that she liked him more as a blonde, Sal adjust his hair and it turns blonde. A variety of humanoid monsters are in the bar, and Sal goes to the bar.
A man, Julian Duval, comes over and Sal assures him that he doesn't want any trouble. Julian tells him to get his shifter ass out of his bar, and Sal dismisses him as a werewolf and attacks him. Their bodyguards finally pull them apart and Julian assures Sal that he's got a lot more. As Julian walks off, a hooded man rips open the fuse box and douses the lights, and then enters the bar. He casually knocks aside anyone who tries to stop him, claws extended, and guts Marv.
Ennis leads Tamara out and takes her to a nearby ferry stop. He reminds her that they met on a ferry in fifth grade and he fell in love with her. As he gives her his engagement ring, Sal staggers out, bleeding. Ennis has Tamara call 911 and goes to Sal as he collapses. Sal mutters something about David and not having a choice, just as the hooded figure arrive. He slams Tam into a door, splitting open her head, and slashes Ennis. He then goes to Sal and guts him, and Ennis runs to Tat am and realizes that she's dead.
At the North Chicago University, Professor Graham enters his office unexpectedly and discovers that his secretary is still there over the lunch hour. He tells her that something came up and goes into his office, and then starts downloading a file from the laptop onto a flash drive. "Graham" then transforms into a young man, David Lassiter, and calls his friend Matt to offer him test answers. David discovers that he has several calls from Margo. Once he gets outside, David calls Margo and she tells him that that their brother Sal is dead.
Ennis gives his statement to a detective, Freddie Costa, who doesn't believe that he saw someone with claws attack and kill Sal and Tam. The detective doesn't believe it and points out that Ennis' father Nate was a great cop but he had a temper, just like Ennis. Costa warns him that if he keeps talking about monsters, he can't help him. Sam and Dean come in, posing as FBI agents, and say that they'll take the case. Dean ushers him out and Sam tells Ennis to describe what he saw. The brothers assures Ennis that they'll believe him, and he describes what happened. Sam assures him that there's nothing he could have done, and Ennis asks what they're going to do about it. Dean tells him that there's no such thing as monsters and the brothers walk out.
Costa meets with Margo and warns that the ghouls may not be with them. She reminds him that her family pays him for influence and Costa warns that the other families have concerns now that Margo's father is in bad condition. Margo tells him that she runs the family now and will crush anyone who gets in her way. David come in, much to Margo's surprise, and Costa offers his condolences. Margo figures that Julian left the club then circled around and killed Sal, and she vows to make him pay. They go in the back room where two of her men are loading their guns. Costa tells David to talk some sense to his sister, and Margo says that she's going to war and tells him to talk to their father if he doesn't like it.
Brother and sister go upstairs to where their father is on life support. Margo points out that David has been gone for three years and their father's condition got worse. As she walks out, David asks if she's sure Julian is the killer, and she says that Costa has a witness. David isn't so sure and Margo accuses him of defending the family that held them down for years. Before she goes, Margo tells David that his ex, Violet Durant, is getting married to the New York Wolves to seal a deal for her father. David tells his sister to be smart and find out what happened, and she says that he ran away to be a human and he doesn't want any part of it.
At the Duval manor, Julian meets with a tattooed djinn, who wonders if the shifters will make a move. Violet comes in and tells Julian that they need to talk. They go out in the hall and Violet asks Julian if he killed Sal. Julian says that he didn't and doesn't care, but he's going to get the djinns on his side for the coming war. When Violet objects, Julian shoves her against the wall and says that her job is to look pretty and stay quiet.
Ennis goes home and takes out a trunk with a photo of his father Nate, and his father's guns. There are also hollow-point silver bullets, and Ennis examines them carefully. He then breaks into the back club and finds claw marks on the floor. A waiter comes in and Ennis hides, but the waiter sniffs him out. Ennis draws on him and orders him to surrender, and the waiter bares his fangs and snarls. When the cop shoots him, the bullets have no effects. As the waiter shoves Ennis against the wall, Sam and Dean arrive and decapitate the vampire.
Dean advises Ennis to go, but he refuses and demands an explanation. Sam does the introductions and explains that they kill monsters, and Dean admits that whatever killed Tamara is new. They figure that Marv is a wraith and Ennis saw his true face in the mirror or on cameras. Sam advises Ennis to try a silver bullet if nothing else works. Dean checks the refrigerators and finds bags with human body parts. They realize it's a monster VIP club, meaning Sal wasn't human and monsters are killing monsters. Ennis wants to go with them to check the body, and there's nothing they can do to stop him. Sam says that he's been there but what they do is messed up, and Ennis is better off out of it.
Back at home, Ennis checks the Internet for information on Sal and discovers that he was the vice president of a blood management solutions company. Costa comes over and asks for a description of what killed Tamara. He claims that he's chasing down every lead and comes in, and Ennis repeats his description. Ennis suggests that Costa stay and meet with Nate, who is working the graveyard shift. "Costa" says that he'd be glad to meet Nate, and Ennis checks the detective's image on his cell phone and discovers that he has silver eyes. He offers to show the imposter the jacket that the killer tore up and goes to his father's trunk. Ennis then loads his father's gun with silver bullets and tells Costa that he knows he's a monster. David reverts to his normal face and explains that he's a shapeshifter and he's trying to find out who killed his brother Sal. The shapeshifter tells Ennis that he's in over his head and Chicago is divided up between five monster families. They own the police and run shakedowns and organ trafficking. The families keep a low profile by minimizing casualties, and right now he's the only one trying to stop the coming war.
Ennis isn't impressed and David tells him to keep out of it. He picks up Ennis's jacket and says that the slashes are flicked with silver, so Julian couldn't have been the one responsible. David then tosses the coat in Ennis's face and runs. By the time Ennis has gotten outside after him, David has made good his escape.
That night, Ennis gets Julian's address and goes to his manor. Sam and Dean are parked nearby, and Ennis listens in as Sam tells Dean that he talked to the coroner and confirmed that Julian paid $3,000 to look at Sal's body. Meanwhile, Violet leaves the manor past the butler, and realizes that it's David. He reverts to his normal face and Violet tells him that he shouldn't be there. David asks her to arrange for a sit-down between Julian and Margo, but Violet warns that Julian doesn't want a solution. He reminds her that he had a choice to leave town with her but she didn't take it, even though she was the one who wanted to go.
Before Violet can respond, the hooded killer drops down from above and knocks David down. Violet runs and the killer goes after her, and David tackles him. The killer touches his silver claws to David's chest... just as Ennis arrives and fires. As David stares at him, the killer runs off and Ennis and David hear Violet scream. They run into the nearby woods just as Sam and Dean arrive after hearing the gunshot. They realize that they have to leave as Julian's bodyguards come out.
The four men pull over and David brings Sam and Dean up to speed on the Five Families control Chicago. Ennis suggests that they track the GPS on Violet's phone, and David refuses to give them her number unless they take him with them. The cop objects but Dean points out that sometimes you have to work with the bad guys to get the worse guys. They get in the Impala and drive off.
Violet is tied up to a pole in a basement when her cell phone rings. She wakes up and sees a board nearby with photos of a young boy on it. The killer comes in and says that he's not a freak like her. He removes his hood and says that he's just a man, and holds up his silver claws.
The Winchesters, David, and Ennis follow the GPS signal and the brothers get out their weapons. Meanwhile, David thanks Ennis for helping and says that he lost someone as well, but he's trying. Ennis offers his condolences about Sal and says that he said to tell David that he was sorry and he didn't have a choice. The four men then head in.
The killer, Irv, explains that silver burns those that are monsters and touches a claw to Violet's face. He forces her to look at the board and says that the boy was his son. Sal was one of the men who ripped the boy apart, but Violet insists that neither Sal nor Julian would hurt an innocent. Violet realizes that the man is trying to start a war, and warns that many more children will die. Irv stares at her for a moment and then turns away... and hear a door open upstairs.
Dean and David go one direction and Sam and Ennis go the other. David tails behind Dean and spots the killer moving through the shadows, and goes after him on his own. Irv attacks and disarms him, and Dean soon realizes that he's lost the shapeshifter.
Irv drags David to the basement and strings him up, and says that he'll have to make an example of him. When Violet objects, the killer threatens her and David protests. Their captor says that they sounded almost human when they were talking earlier at the manor, and scratches David with his claws. Violet starts to transform while Irv says that deep down they're just a monster. The woman rips herself free and attacks Irv until David breaks free and pulls her off. Violet gets hold of herself and David holds her, just as Sam, Dean, and Ennis arrive. Irv looks up at Ennis and says that he's sorry about Tamara but she got in the way. He figures that Ennis understands and says that they're all monsters, but Ennis says that he only sees one monster there and shoots Irv dead.
The next day, David meets Violet at Julian's manor and they go for a walk. She says that she'll be all right and David says that Sal said he was sorry. David wonders why Sal said that, and Violet remembers how Sal met her at the station and told her that it's his job to keep the family bloodlines pure because it's the one thing they all agree on. If she didn't leave, Sal threatened to kill her whether she loved David or not.
David says that he knew Sal would always have his back, and Violet doesn't tell him about what Sal said to her. She turns to go and David says that's what she does best. After a moment, Violet turns and kisses him, drawing blood, and then walks away.
Later, David goes to see his father. He wakes up and warns his son that Margo wants war and David has to stop her. David then gives Margo Irv's claw and says that the Duvals are clean. He also tells Margo that he's coming back to the family. When she notices her bodyguards smiling in approval, Margo puts on a smile and welcomes David back.
Sam and Dean drop Ennis off at his home and he explains that his sister lives on the other side of town, his mom's out of the picture, and his dad died in the line of duty. Dean gets a call from Castiel saying that he has line on Metatron. Sam wants to deal with monsters in Chicago, and tells Ennis that they'll call in some other hunters. Ennis starts to say that he can deal with it, but Sam warns him that if he gets in too deep then there's no getting out. The Winchesters drive off and Ennis realizes that it's his fight. He goes back to Irv's basement and looks at the photos, and touches the ring he was going to give Tamara. A man calls and warns Ennis that if he starts hunting, the monsters will kill him. Ennis thinks that it's his father's voice, but the caller hangs up without saying anything further.



