Sam is working late and tells Sock and Andi to head for the karaoke bar and he'll meet them later. He closes up but notices something moving around and going to investigate. In Gardening he spots an ominous shadowy winged figure… which forms into a delivery man with horns. The demon has Sam's contract: a huge multi-page volume, but needs Sam to sign all of the paperwork. Sam realizes that it will take hours and he won't get to the karaoke bar.
The next morning Sock stops by to pick up Sam and they realize what Sam's new demon power is: he keeps slipping all over the place. Sock drags him into work while telling Sam that Andi ended up with college preppy Greg at the bar the previous night. Sam gives Andi another excuse for missing their get-together but she isn't impressed.
The Devil calls Sam into the restroom then teleports him into the sewers. He suggests that he help Sam "deal" with Greg once and for all, but Sam backs away from that idea. The Devil then shows him two murder victims that apparently slipped and fell to their deaths. The Devil directs Sam toward a trail of goo which he follows up to the surface. He spots a shadowy figure of a man walking across the street and getting hit by a car. The figure explodes into green slime and the car slips out of control and crashes, killing the driver. Sam goes over and finds a business card identifying the driver as an attorney. The slime reforms into a blob and slithers down into the sewer.
Back at the Work Bench, Sam picks up his new box, which contains… a Christmas sweater. Mr. Oliver comes in to visit and suggests that Sam set up a meeting with the Devil so he can negotiate and help his son. Sam agrees to give it a try and heads out with Ben and Sock, but spots Andi with flowers from Greg. He can't explain what's going on but promises to get together with her that night to tell her everything.
Sam puts on the sweater and they guys head into the sewer and follow slime footsteps to a political fundraiser. Robert Hartford is running for city council and when Sam tells him about the lawyer's death, Hartford could care less. He orders his security to take the guys away but Sock goes after him with the sweater. They end up getting arrested and Sock drops the sweater.
Josie negotiates a deal to get them out of jail: Hartford doesn't want the bad publicity but insists they stay away from him. She also reveals that Hartford's father ran a chemical company and he died, and now Hartford is involved in a lawsuit against the company. The guys figure that Hartford's father is protecting his son by going after the people involved in the lawsuit, including the dead lawyer and the two murder victims that the Devil showed Sam.
Sam realizes he's three hours late for his meeting with Andi and heads to her house, while Sock and Ben go to Hartford's to recover the sweater. Sam gets to Andi's but Mrs. Prendergast to tell him that Andi went out with Greg. Sam goes back to the car and finds the Devil waiting for him, with photos of Greg with twins. Sam refuses to use the information to get rid of his rival and tries to get the Devil to speak with his father, but is angrily rebuffed.
Sam goes to Hartford's and together with Ben and Sock finds the sweater, but the soul attacks Ben and almost kills him before Sock manages to drive it away. Sam heads home and has to tell his father that the Devil doesn't want to see him. Mr. Oliver is both nervous and angry and insists on going through the contract for Sam so he can find a loophole. Sam agrees and the next day meets with Josie to find out about Hartford. Josie reveals she and her current boyfriend are going on a double date with Andi and Greg. Sam blurts out about Greg and the twins and she accidentally spills coffee on an upset Sam. He notices that the sweater absorbs the coffee instantly and finally figures out what he's supposed to do with it. Sock shows up and manages to let Sam know that a new lawyer, Gwynne, is taking over on the Hartford lawsuit. They quickly get out of there, collect Ben, and head to Gwynne's house. She's taking a shower and the guy spot slime on the outside pipes. They break in and manage to save her when the escaped soul attacks her through the shower drain. They follow it into the sewer with Sock holding the sweater, and Sam ends up cut off from the others. The soul attacks him but Sock puts on the sweater and grabs the creature and Sam, absorbing the soul. Unfortunately it makes the sweater as hard as a rock and Sam and Sock have to get to the DMV where Gladys the DMV Demon pulls out a claw-glove to remove it from them… painfully.
Sam goes back to the Work Bench, where Andi is furious because Josie told her about what Sam said. The twins are Greg's sisters, and Andi figure Sam was trying to break her and Greg up. Andi storms off and Sam goes home to find the Devil waiting for him. The Prince of Darkness admits he set Sam up so he wouldn't tell Andi about his secret life, and that it's for her own good: mortals that get involved with the Devil tend to get in trouble. He figures that Sam is best off keeping the whole thing secret: everyone has secrets.
Downstairs, Mr. Oliver is going over the contract… then finds one specific page, rips it out, and burns it in the fireplace.
At the Work Bench, Andi knows about the "twins" and reveals they're Sam's sisters. Andi insists that Sam stay out of her private life and walks off. The Devil is waiting for Sam at home office and notes that he wasn't going to let Sam tell Andi about their arrangement. He warns that it's never good for mortals to get involved with him. Still, the Devil admits he thinks Sam should keep her safe, and he's just looking after them. Meanwhile, Mr. Oliver goes through the contract… and secretly burns a page.