Oliver Crangle spends his time calling people and telling them that certain of their workers are Communists, subversives, and "morally objectionable." He endlessly compiles information to aid his investigation, while his parrot Pete looks on. Crangle looks out the window and obsesses about all the evil people out there, and says he plans to take the next major step at four o'clock that day, destroying all evil. His landlady brings up a delivery and she wonders what he does all day. He explains that he investigates people and reveals the evil within them that he finds. Crangle notes that at four o'clock the evil in everyone will be revealed.
A Mrs. Lucas comes to see Crangle and asks why he's prosecuting her husband. Crangle says that he doesn't know her husband, a doctor, but he has done a lot against society. Crangle goes through his files and reveals that Mr. Lucas supposedly let a woman die in the ER. Mrs. Lucas says that her husband didn't get to the woman too late, but Crangle says that Mr. Lucas is evil and he plans to make sure he is removed from his position. Mrs. Lucas pleads with him to stop, saying her husband's job isn't threatened but he's sensitive and the pressure is getting to him. She wonders why he does what he does and Crangle rants about the evil people, calling them ants. He has an idea and decides to make every evil person two feet tall at precisely four o'clock.
Mrs. Lucas runs out and as 4 o'clock approaches, Crangle considers the Gettysburg address and it's line about all men being created equal. A visitor arrives, Mr. Hall, who is an FBI agent. Crangle explains that he's trying to notify all the authorities about his plan to shrink all evil people at four o'clock. Hall wonders how Crangle plans to shrink anyone and he explains that he will simply will it. In the past he had considered making airplane propellers limp, or change wheels to triangle or square. The FBI agent asks if he's seen a psychiatrist and figures that he's obsessive, and isn't sure what Hall wants to do. Crangle wants the authorities to arrest all the evil people now that they're recognizable. Hall tells him they're not going to do anything and they don't want him interfering. Crangle figures that Hall and his superiors are evil as well.
Come 4 o'clock, Crangle boasts to his parrot that all the evil people are shrinking. He turns back to the window... and discovers that he's shrunk.