Sam is running in terror and gets to the car, insisting that they can't hurt him. He turns around and looks, and sees a clown waving to him. It charges at Sam and he runs toward a warehouse, and just manages to slam the door shut. However, it smashes in and advances on him, and another one comes up behind him.
Sixty hours earlier
Sam and Dean are waiting at a phone booth. Frank finally calls them with an update on the status of the Leviathans. Sam has come up with something and they head to Wichita. Brian Harper has been killed by a 30' long octopus that bled him out, but the coroner dismisses it as a fetish attack. The brothers go to talk to the widow, Debra Harper, and they act if she has noticed any supernatural signs. They then ask if Mr. Harper had any enemies and she finally tells them to talk to Stacey, their nanny, who was there the night he died. As they leave, a young girl watches them from the top of the stairs. Outside, Sam wonders why Mrs. Harper would have summoned an octovampire to kill her husband even if she could.
Dean goes to talk to the nanny, who insists that there was nothing going on between her and Brian. She explains that they had a birthday for their daughter r Kelly at Plucky Pennywhistle's Magical Menagerie, a local pizza joint. Brian was only there for five minutes and left, and Debra was out of town. Kelly freaked when another kid said that her parents didn't love her. Dean asks if she noticed anything weird and the nanny admits that Kelly thinks that there are monsters in the closet.
As Dean leaves, he tells Sam that they should talk to Kelly because she was angry at Brian for missing her birthday party. Sam approaches the house and Kelly remembers him from earlier. Debra calls to her daughter and Kelly says that Debra will get mad at her because she told the police that she warned Brian that the monster would get him. Debra comes out and orders Kelly inside. As she leaves, Sam notices that she's been drawing an octopus-like monster on the sidewalk with chalk.
That night a unicorn is chasing a man through the forest. He climbs over a fence into a baseball field and seemingly evades it, but it rams its horn through the wood and impales him.
Sam tries to fight off the clowns and shoots one of them, but the bullets have no effect. They knock the gun out of his arm and knock him around.
Thirty-six hours earlier
Sam and Dean get the call on the murder. Dean goes there and confirms that the police have no idea what ran the man through. The dead man did have an eight-year-old son, Billy. Dean talks to the widow, Mrs. Pogue, and asks if Billy had a birthday. She says that he didn't, but that her husband took Billy to a friend's birthday party. Dean then calls Sam at the motel and asks him about Plucky Pennywhistle's. Sam insists that he hated them and that Dean dumped him there when he went looking for chicks. Dean tells him to check out the local Plucky's while he talks to Billy. When Sam refuses, Dean realizes that it's Sam's fear of clowns kicking in and assures him that if it bleeds, it can be killed.
Sam goes to Plucky's and the attendant, Howard, greets him. He asks for the manager and notices an attendant, Libby, asking her son to stay there while she works. Sam notices a board where the children have driven their worst fears, and an empty slot where Kelly's picture was. The manager, Jean Holliday, comes over, and explains that they don't post the really horrible stuff. He wonders why they ask the kids to draw creepy things and Jean explains that the owner is obsessed with aiding children's development and helping them overcome their fears. Sam asks her about Billy and Jean explains that Billy's father pulled Billy out before the cake was served and then threw a fit. As Sam calls Dean, the janitor calls him over and says that they're being watched but that he needs to talk to him after closing.
Afterward, Sam goes back to the motel and tells Dean what he's learned, and that the pictures that belonged to Billy and Kelly weren't there. Dean explains that he talked to Billy, who drew him a picture of a unicorn.
The janitor, Saul, is leaving for the night but Jean tells him that he has to clean the puke out of the ballpit. As Saul goes to work, something moves through the pit behind him and bites his leg. He tries to get out but it pulls him under and then spits him out.
Sam and Dean arrive at Plucky's to meet Saul and see the police out front. The brothers check the body and confirm how he died. The police think that the ball washer did it, but the bite marks are those of a 20' shark. They go inside and confirm that the picture belonging to Omar Cooper is missing. Sam figures that Omar is afraid of sharks and that whoever is responsible wanted to silence a whistle blower. The brothers search the place and scan for EM.
The next morning, Libby arrives for work and gives Tyler some coins so he can take the bus to school. They go in, while Tyler leaves his sketch of a giant robot with laser eyes on the seat.
The clowns continue to beat Sam until he grabs a tire iron and fights back.
Four hours earlier
Back at the hotel, Sam and Dean try to figure out what's responsible but don't come up with anything. They didn't find anything at Plucky's and Sam suggests that he go back, play bad cop, and lean on them. Dean isn't impressed with the plan but Sam tells him to hang back, act normal, and follow anybody who reacts.
When Sam arrives at Plucky's, Jean tells him and Libby that they've roped off the ballpit. He insists on talking to Jean privately. As they go in back, Dean watches them and tries to blend in. However, the arcade games soon catch his attention. He goes to the counter and talks to Howard, who insists that he can only get a prize with tickets, not cash.
Sam demands answers from Jean, who insists that she was by the cash register and is on the security cameras. When she mentions that she's new at the job and recently promoted, Sam asks if there was a lot of competition and Jean admits that she had to write an essay. He continues to pressure her but gets no reaction.
Dean is playing skeeball for tickets when Jean comes out. He follows her out the back and watches her smoke marijuana. While Sam interrogates Howard, Tyler sees a kid cheating and tells him to stop. The kid is unimpressed until Dean comes over and yells at him. Libby serves her son some pizza and goes back to work, and Dean notices and suggests that Tyler cut her some slack. He explains that his dad used to haul him places and that Libby is working hard. Dean notices that Tyler is drawing a robot and the boy admits that he's scared of them.
Sam interrogates one of the mascots, Cliff, and the guy cracks, throws his stuffed head at Sam, and runs out the door. Dean and Sam run after him and finally tackle him, and the guy insists that his brother was the one running a meth lab in Butte. Cliff has no idea about people dying from children's worse fear, but mentions that there's a sub-basement and that he and Saul found out about it. They heard spooky stuff through the vents coming up from the boiler room.
Libby is taking her son out and he complains that someone stole his sketch. When Tyler sees Dean, he apologizes to her and they leave. Dean confirms that the drawing is gone and figures that Libby will be the next victim. Sam goes after Libby while Dean goes to the boiler room. He breaks in and finds a glowing brazier and children's sketches on the wall. Howard comes in behind him with a gun and explains that he can draw on the children's fears, toss their sketches in the fire, and use something that the parent owns. He insists that he's just doing what he needs to, and Dean manages to disarm him. He rips apart Tyler's sketch, but Howard says that he has bigger plans and torched Sam's business card, and then chose a special picture from his collection just for Sam.
Sam gets out of his car and finds himself face-to-face with a clown.
Right Friggin' Now
Dean notices that Howard has a collection of Plucky dolls. Howard complains that management passed him over and glances nervously at the dolls. The man insists that the parents deserved what they got, and that a good parent puts his children first. Howard figures that the children would have been better off, and Dean realizes that Howard's brother is dead. One of the sketches shows him drowning and Howard insists that it wasn't his fault and that his parents didn't listen. He insists that his parents let his brother die.
Sam continues to fight off the clowns.
Dean grabs the sketch and taunts Howard, saying that he's afraid. He throws the sketch and one of Howard's dolls into the fire and Howard opens fire. Howard's brother appears, soaking wet, and advances on Howard. Howard insists that it wasn't his fault but his brother touches his hand and Howard falls to the ground, drowning as water pours out of his mouth.
The clowns charge at Sam... and disappear in a burst of confetti.
Sam, covered in confetti and seltzer, drives back to find Dean at Plucky's. Dean can't stop laughing. As they get ready to leave, Dean apologizes for psychologically scarring him by ditching him when they were kids. Sam admits that it was therapeutic and figures that a clown can't do anything worse to him. He then gives Dean the giant slinky that he won. Dean has a Plucky doll for him and Sam leaves it behind as they drive off.