A lady trapeze artist violates the code of the side show when she plots to murder her midget husband.

As horrified people gather round the cage containing one of the members of a carnival's freak show, the barker explains that the pitiful specimen inside was once a beautiful aerialist named Cleopatra, who was known as the "Peacock of the Air," and relates to the crowd: Hans, one of the carnival's dwarfs, is infatuated with Cleopatra's beauty and normal size, much to the dismay of his fiancée Frieda, who is Hans's size. Cleopatra delights in toying with Hans's affections and making Frieda jealous, and she continually borrows large sums of money from Hans. One day, Hercules, the strongman, ends his relationship with Venus, one of the other "normal" members of the carnival, and takes up with Cleopatra, who shares his cruel attitude toward the "freaks." Venus is comforted by one of the clowns, Phroso, and her friends, the freaks. Venus, Phroso and Roscoe, another clown who is married to Daisy Hilton, one of the carnival's Siamese twins, begin to worry about Hans, who is increasingly ignoring Frieda to moon over Cleopatra. Hans breaks off his engagement to Frieda, after which Frieda goes to Cleopatra and begs her to cease leading Hans on. Cleopatra laughs at her, and after Frieda inadvertently tells Cleopatra about Hans' fortune, Cleopatra and Hercules plot against him. Cleopatra and Hans marry, and at the wedding feast, Cleopatra is horrified when the drunken freaks tell her that she is now one of them. She shouts at them, then humiliates Hans by carrying him around on her shoulders. She later reveals to Hans that their marriage is a joke, and after he collapses in hysterics, another dwarf, Angeleno, overhears Cleopatra and Hercules discuss the poison they gave to Hans. The next morning, a doctor examines Hans and reveals that although he was poisoned, he will recover. Venus confronts Hercules, but he refuses to tell her what poison Cleopatra used. A week passes, until one night, after Cleopatra gives Hans some medicine she has doctored, he and the other freaks plot their revenge on her and Hercules. A thunderstorm begins, and some of the freaks chase after Cleopatra while the others prevent Hercules from harming Venus. Hercules is killed, and after a chase, Cleopatra is mysteriously transformed into a grotesque "duck woman" who is put on display with the other freaks. Some time later, Hans and Frieda are happily reunited, while Phroso and Venus continue their romance.