A circus aerialist is charged with robbery and murder.

Mentally retarded Willie Simple still harbors his childlike daydream of becoming a clown. Slate takes pity on him, giving the boy a job although he has been warned that he might cause problems.

Johnny Slate (Jack Palance) is trying to decide which act to send to Russia for a cultural exchange program with the Moscow Circus. Horse trainer Kate Reynolds (Lucille Ball) wants the coveted spot. Menagerie feeder Charles is mauled by one of Kirov's trained bears and dies, leaving his young son Jeff alone in the circus. Coldy ambitious Kate takes care of the boy until Slate locates his Aunt Agatha, a spinster living near Washington DC. Jeff wants to stay with Kate and their separation is surprisingly difficult for her. Kate reveals to Slate that she was a 17 year-old widow with a child on the way, but that she lost the baby. Unhappy, Jeff runs away from his Aunt and returns to the circus in hides with the help of Kirov. Kate and Agatha agree that Jeff belongs with the circus and Kate will be his guardian.

Joan Blondell, Buster Keaton and Joe E. Brown portray a trio of veteran performers, now reduced to handling menial chores around the circus. Slate's most pressing problem, however, is an uninterested young man who's been turned over to him to ""learn the business."" Over this barrier of gloom climbs spirited and ambitious Ivy Hatch, who has run away from home to join the circus. Ivy has one drawback: She doesn't have any special talent.