Oak Park, Illinois
A man, Walter Rosen, comes out to dump his garbage and notices his neighbor's car. He shrugs and puts his garbage in the cans… which start to vibrate. The lights flicker and a black cloud forms overhead. One black streamer comes down from the car and enters his mouth. He then gets to his feet, his eyes solid black, and watches as the other streamers spread throughout the city.
One Week Later
Sam is reading up on demon rituals out in the Impala, while Dean is in a house getting lucky. Bobby calls Sam and warns he won't find an answer to Dean's problem in a book. He tells Sam to pack it up and gets Dean out of his date with twins. They head to Lincoln, Nebraska where strange insect activity has been reported. As they drive Dean wonders why they haven't found any activity from the escaped souls. When they arrive in Lincoln they meet up with Bobby and check out a house. They find the rotting corpses of the family watching TV. Dean goes outside and is attacked by Isaac and Tamara, a married couple who are demon hunters. Dean checks with the coroner later and determines the family starved to death despite the fact there was plenty of food in the house. Isaac doesn't want to work with them, since they released the demons. The couple leaves and Dean, Sam, and Bobby hole up, unaware that a blonde woman is outside watching them.
Walter walks into a store and touches a woman, suggesting she check out a pair of shoes another woman has. The first woman goes after the shoes… and kills to get them.
The guys check out the crime scene while Bobby checks the "killer" and determines she wasn't demon-possessed. Dean directs them to the security camera and catch Walter on tape. They leave, and split up as Sam notices the mysterious blonde woman is still following them.
Bobby and Dean stake out the bar where they located Walter. Sam shows up to report that Walter disappeared when the gate was opened. They spot Walter going in… with Isaac and Tamara following him. In the bar, Walter notices the fact they're carrying holy water and goes into the restroom. Isaac follows him in but a demon attacks him and it turns out everyone else in the bar is one of the new demons as well. The guys try to burst in through the locked door, while the demons somehow force Isaac to drink drain cleaner as Tamara looks on. Isaac dies while the guys bust down the door with Bobby's car and uses holy water to keep the demons at bay. When Dean runs out of water he tosses Walter into the trunk and they drive away.
Back at the house, they hold Walter in a Devil's Trap while Tamara insists on going back to the bar. Bobby figures out there are seven of them, and they're up against the Seven Deadly Sins. All of the deaths are related to one of the sins: Envy, Sloth, and Gluttony. They try and interrogate Walter, Envy, but he taunts them with the fact they have plenty of sins of their own. He warns the other Sins will be coming from him, but they let Tamara dispose of Envy. Dean offers to delay the Sins on his own but Sam refuses to hear of it. Tamara finishes sending the Sin back to Hell… and she's unconcerned that Walter died as well.
The guys barricade the house and seal all the doors with salt, then wait for the Sins to arrive. An agonized Isaac arrives outside and yells for Tamara, saying he managed to escape. They figure it's a demon possessing his corpse, but "Isaac" torments Tamara over how she let the demons kill their daughter. Enraged, she goes outside, breaking the salt line, and stabs the demon through the chest. The other Sins burst in and one, Gluttony, comes after Bobby, who lures it into a Devil's Trap then banishes it. Dean squares off against Lust, who comes on to him and he kisses her. Sam lures the others beneath another Demon Trap but the main one, Pride, destroys the ceiling it's painted on. Pride is unimpressed with Sam's reputation and warns he no longer has the protection of the Yellow-Eyed Demon.
Dean distracts Lust long enough to shove her into a tub filled with holy water, while Pride starts to strangle Sam. The mysterious blonde woman comes in, disposes of one demon, and draws the other two off of Sam, killing them with a mystic knife. She then takes off before Sam can get her name.
The next morning they salt and burn the bodies of the humans who didn't survive the exorcism, while Tamara disposes of Isaac's body. Bobby isn't aware of a blade that can kill a demon, while Sam wonders what else they might have let out. Tamara and Bobby head out and Sam suggests they head to Louisiana to find a voodoo priestess to help Dean with his deal. Dean doesn't believe anyone can get him out of the deal and explains that if he gets out of the deal, Sam dies. Sam thinks his brother is a hypocrite, but Dean says he actually feels good for the first time in a long time, so they should go out and raise a little hell.