An unidentified man in Green Bay, WI has captured worldwide attention for roaming the streets dressed as a clown. Many write it off as a harmless prank, others aren't so sure. When a group of friends cross paths with the clown everyone calls Gags, his true intentions are revealed.
A small city in Wisconsin is terrorized by a mysterious clown who roams the streets late at night with nothing more than a handful of black balloons. The local news stations scramble to break the story on who he is and what he wants while a group high schoolers see the clown's arrival as an excuse to create a little trouble themselves. The police try to maintain order in a city that has gone clown crazy and a conservative podcast host vows to put a stop to the clown known as Gags while broadcasting his "clown hunt" on social media for the world to see.
Jon, his girlfriend Ashley, and their friend Cory return to their car in Green Bay's Pine Street parking garage to find the vehicle's interior filled with black balloons. Gags, a clown whose random appearances have been unsettling citizens for eight days, stands ominously nearby. Jon coughs up blood after one of the balloons pops and covers him in white powder. Gags kills Cory. Ashley flees and Jon disappears.
WGRB field reporter Heather Duprey covers the ongoing Gags story with her cameraman Dale Russell. Egged on by his viewers and accompanied by his cameraman Wayne Barlament, right wing podcaster Charles Wright hits the streets to track down Gags and exact vigilante justice.
Officer Meredith finds an entranced man dressed as a clown and covered in white powder sitting in a stalled car. The entranced clown exits the vehicle and ominously approaches the officer.
Officer Deighan investigates a movie theater break-in. Clown footage plays on the screen before Gags attacks the officer.
Teenager Tyler Zepnick and his girlfriend Sara Renard prank friends at a party by having their friend Chris Schuldt impersonate Gags. Police officers Chrissy Renard and Jake Gruber break up the party. Renard, who is Sara's stepmother, sternly instructs Sara to go home.
Heather interviews antique store owner Ralph Jungwirth. Identifying Gags in an old photograph, Ralph claims Gags has been haunting Green Bay since a mysterious fire destroyed his circus in 1974. Heather dismisses Ralph as a crackpot. Heather encounters rival reporter Rebecca Chambers from WBSC on her way out of the store.
Sara regroups with Tyler and Chris. Instead of going home, Sara agrees to help Tyler record Chris pranking more people around town in his clown costume. After scaring multiple people, the teens decide to go to a local fair.
Officer Jacobs responds to a call from a woman whose daughter Erin had been behaving strangely since returning home covered in white powder. Erin confronts her mother and Jacobs after mutilating her face and neck while seemingly entranced.
Station manager Ron calls Heather to angrily remove her from Gags coverage after Rebecca Chambers scoops Heather by being first to interview Charles Wright about his vigilante crusade. Heather tells Dale they are going to stay on the story anyway by shifting their focus to Charles.
Renard and Gruber investigate a banquet hall break-in. They discover Jon behaving strangely with his face made up like a clown. Gruber shoots Jon, but Jon is unaffected and escapes. When Renard calls in the encounter, she learns people all over town are disappearing after suffering from disorientation and self-mutilation.
Chris finds one of Gags' black balloons at the carnival. The balloon pops and covers Chris in white powder. Chris begins vomiting black blood.
Charles Wright finally finds Gags. Wayne livestreams Charles' confrontation with the clown. Charles prepares to fire his gun at Gags, but hesitates when he hears carnival music. Gags vanishes. Wayne echoes comments posted by viewers by calling Charles a coward for not pulling the trigger.
Charles decides to pursue Gags to the abandoned Larson-Green mill. Heather and Dale follow Charles there.
Sara insists on taking Chris to the hospital, but Tyler demands they go to the mill to find Charles and Gags instead. Chris sides with Tyler. Tyler insults Sara, so she goes home alone.
Inside the mill, Tyler encounters an entranced man in clown makeup. A clown screaming for help rushes at Charles. Charles shoots the clown. Charles shamefully confesses to Wayne that he never killed anyone when he was in the Marines as he was actually a mechanic. Charles and Wayne flee when Renard and Gruber arrive. Renard unmasks the dead clown as Tyler.
Heather and Dale follow carnival music to a circus tent in the mill's basement. Inside they find all of the entranced victims, including Chris and Jon, assembled around a stage with their faces transformed to look like clowns.
Renard falls down a hole and dies. Gruber chases Charles and Wayne into the tent. Charles tries pinning Tyler's murder on Wayne while insultingly demeaning him. Wayne pulls his gun and shoots Charles. Gruber shoots Wayne. Dale drops his camera and flees.
Heather continues recording as Gags appears onstage. A popped balloon drops white powder onto Gruber. Gruber stumbles into the side of the tent and brings it down. Chaos ensures.
Heather rushes past Rebecca Chambers as she flees outside. Heather stops when Gags suddenly appears in front of her. Gags gives Heather a balloon that looks like her and vanishes. The balloon explodes and kills Heather. Rebecca smiles as she begins broadcasting live.
