Circus begins with Spears at a vanity, putting Curious on and earrings by Bulgari. She is then seen holding a top hat in front of her face, while doves fly out of another hat. Spears starts singing in the vanity but stands up and puts on a ringmaster jacket. She walks through an aisle while dancing suggestively with several circus dancers. Throughout the video, there are interspersed scenes of different circus performers, including ribbon dancers, contortionists, clowns and a mime on stilts. There are also scenes of Spears singing with the top hat, wearing a nude body stocking in front of a red curtain, with a spotlight on her. This is followed by a group dance scene in the middle of a circus ring, where Spears wears the ringmaster jacket, sequined hot pants and a feathered top hat. In the second verse, she dances with a chair and a whip wearing a nude bra covered in leaves. The video continues with a series of intercut scenes, such as Spears in slow motion in front of a shower of sparks, her surrounded by a pair of lions and in front of an elephant. During the bridge, Spears and her dancers perform a routine in front of flames. In the last chorus, Spears returns to the circus ring, surrounded by two elephants, many more circus performers, dancers and fire breathers. The video ends with Spears in the spotlight, laughing with the top hat over her head.