In New York City, Nick Nikas sits uncomfortably in a court-ordered therapy session while Peter, a psychiatrist, attempts to conduct tests to determine the extent of Nick's cognitive and social impairment and arrive at a diagnosis. Just as Peter is trying to get Nick to talk about a violent incident with his grandmother, Nick's brother, Connie, bursts in and forces Nick out of the room. The Nikas brothers rob a bank for $65,000 and get into a waiting Uber. A dye pack in the bag of money soon explodes, causing the driver to crash, and Connie and Nick flee on foot. After washing the dye from their clothes, they are stopped by the police, and Nick runs. He is arrested and sent to Rikers Island, while Connie escapes.
That night, Connie attempts to secure a bail bond to get Nick out of jail. Most of the money from the robbery was destroyed by the dye, but he convinces his girlfriend, Corey, to pay the remaining $10,000 with her mother's credit card, only to discover her mother canceled the card. When Connie learns a fight with another inmate landed Nick in the hospital, he leaves Corey and goes to Elmhurst. Finding Nick's room guarded by a police officer, Connie waits for the officer to step away, then sneaks away with the patient, who is unconscious and bandaged, in a wheelchair. They get on an Acces-A-Ride bus, and Connie tricks Annie, one of the other riders, into letting them wait in her house until morning. Connie watches TV with Crystal, Annie's 16-year-old granddaughter. When his old mug shot appears on the news, he kisses her as a distraction. They are interrupted by the sounds of the patient regaining consciousness, and Connie discovers he did not break Nick out of the hospital, but rather a different criminal named Ray.
Ray recounts the story of his day to Connie, and Connie realizes that the bottle of LSD solution and bag of stolen money Ray's friends ditched in a haunted house ride in Adventureland while they were running from police are probably still there, as the friends were arrested and Ray was injured. Connie tells Crystal he wants to borrow Annie's car to take Ray home, and he, Crystal, and Ray drive to Adventureland. Leaving Crystal in the car, Connie and Ray search for the money, but find the LSD instead. They are caught by Dash, Adventureland's security guard, who says the police are on their way. Connie beats Dash unconscious and, when a police car arrives, steals Dash's uniform. Ray pours LSD down Dash's throat, and Connie tells the officers that Dash, who is hallucinating, is the intruder. Crystal is arrested when she gets out of Annie's car, and Connie watches the police take her away.
Unable to find the money, Connie and Ray go to Dash's apartment, where Connie befriends Dash's pit bull by letting it smell Dash's jacket. Ray, at Connie's insistence, calls his friend Caliph to offer to sell back the LSD, and, while they wait for Caliph and the sun rises, Ray begins drinking. Connie tells Ray that he is a leech on society, and they have a heated argument. Caliph arrives without any money, and Connie, protected by the dog, tells him to come back with $15,000. Although Caliph agrees, he tells Ray that he is really going to get a gun.
Sensing danger, Connie attempts to leave with the acid before Caliph returns. Ray attacks him in the hallway and tries to get the drugs, but Dash's dog attacks Ray. Connie gets away, and Ray escapes into the apartment, where, hearing sirens, he looks out the window and sees Connie get caught by the police. There is a pounding at the door, and Ray attempts to reach a neighboring apartment by climbing out a window, but he slips. As Connie is being put in a police car, he witnesses Ray fall to his death. Peter greets Nick and Nick's grandmother in a lobby. While he walks Nick back to join a class, Peter remarks that Connie did the "right thing", and both brothers are where they belong. Nick is initially very uncomfortable, but he gradually begins to participate in the group activity.
