Told through the memories of Jacob Jankowski, who’s unsure of his age, the date, or where he is at times, Jacob remembers his time during the Great Depression after his parents untimely death and the time he spent with the Benzini Brothers Most Spectacular Show on Earth.
After he leaves Cornell University during his final exams, Jacob is hired by the circus owner, Uncle Al, as the shows veterinarian. While there, he lays his eyes on the beautiful Marlena, the shows equestrian star and the wife of equestrian director, August. Although Jacob struggles to see Marlena as nothing but a friend and colleague, he quickly falls in love with her during his 3 and a half month stint with the Benzini Brothers circus.
Jacob rooms with a dwarf named Walter, and they are later joined by Camel, who helped Jacob get onto the show, and has become paralyzed thanks to his years of drinking Jamaican ginger extract (nicknamed Jack.) In an attempt to keep Camel from being red lighted, Walter and Jacob hide him in their stock car/room.
August proves to have violent mood swings, being up and charming to all to quickly go on a downward spiral. One of these spirals results in August attacking Jacob and Marlena, after which Marlena decides to leave August. Uncle Al tries to force Jacob to get the pair back together, or threatens to have Walter and Camel red lighted. Uncle Al proves true on his threat, and Walter and Camel are both red lighted after Jacob and Marlena declare their love for one another in secret and plan to run off together.
During the final show of the Benzini Brothers Most Spectacular Show on Earth, a stampede is started. During this stampede, Rosie, the elephant Uncle Al procured after another show flopped, kills August because of the beatings and violent out bursts he had while trying to train her for an act.
Marlena and Jacob end up married, and work on the Ringling Brothers circus with Rosie and some of the other animals from the show. They have five children, who eventually put Jacob into a old folks home well after Marlena died and they figured he couldn’t take care of himself any longer. Jacob decides to join another circus, running away from the old folks home when his children forget who is suppose to visit and he bonds with the owner of the circus that set up camp down the street from the home.