When Jacob Jankowski, recently orphaned and suddenly adrift, jumps onto a passing train, he enters a world of freaks, grifters, and misfits, a second-rate circus struggling to survive during the Great Depression, making one-night stands in town after endless town. A veterinary student who almost earned his degree, Jacob is put in charge of caring for the circus menagerie. It is there that he meets Marlena, the beautiful young star of the equestrian act, who is married to August, the charismatic but twisted animal trainer. He also meets Rosie, an elephant who seems untrainable until he discovers a way to reach her.