Water for Elephants is the touching story of Jacob Jankowski, a ninety-three-year-old man, who is reminded of his colorful past when a circus sets up next door to his assisted-living center. When Jacob overhears a man at the assisted-living center claim to have been a water boy for the elephants on a circus, Jacob knows the man is lying because Jacob himself once worked as a vet on a traveling circus. The lie causes Jacob to spend much of his time remembering his colorful past, wishing he could move back in time and return to those days of camaraderie and excitement. It is a story of coming of age, of facing the realities of death, and living despite it all. Water for Elephants is an adventure for readers of all ages.

Jacob Jankowski lives in an assisted-living facility. Jacob believes his predicament is in part due to the fact that his children are too busy with their own lives to take on the complication of caring for Jacob's needs. Jacob is an independent man and feels as though the moment he moved into the center, he ceased being treated as a human being. When Jacob gets into an argument with another patient over whether or not the other man was a water boy for elephants, it feels like the last straw. Jacob does not want to continue to live in this way and longs for the days of his youth.

Jacob recalls his final days at Cornell, where he studied veterinary medicine. The most important thing on Jacob's mind at the time was losing his virginity. That was until the moment the dean interrupted one of his classes to inform him of his parents' death in a car accident. Jacob returns home to bury his parents, only to learn that they had mortgaged their home to pay for his education and were unable to keep up the payments. Jacob has nothing left. Jacob returns to school but cannot concentrate on his final exams in light of all that has taken place, so he walks away.

Lost, both emotionally and physically, Jacob jumps aboard a passing train. The train turns out to be part of a traveling circus. Jacob befriends one of the circus workmen and occupies his day with odd jobs until given the chance to speak with the owner about a more permanent job. When the owner's head animal trainer learns that Jacob was just days from receiving his veterinary license, he insists that Jacob take a look at one of the horses. Jacob proves his skills through his diagnoses of the horse and is granted a job.

Jacob soon becomes friendly with the animal trainer, August, and his wife Marlena. Marlena is a beautiful young woman, who is a circus performer. Jacob finds Marlena enchanting, and he soon realizes that Marlena's marriage to August is unhappy. Jacob lets Marlena know how he feels about her in awkward moments alone, but Marlena is afraid of August. Jacob does not understand Marlena's fear until shortly after the circus adds an elephant to their collection of unusual animals, and Jacob witnesses August's darker side.

Rosie is a young elephant, who, according to her sellers, is too stupid to learn an act. August finds Rosie difficult to manage, often beating her in order to make her submit to his orders. Jacob finds this behavior disgusting but feels there is little he can do to protect her. However, when August beats the elephant for stealing lemonade, Jacob is livid. Jacob goes to Rosie to offer her a favorite drink and finds a roustabout with her, speaking gently to her in Polish. What Jacob finds most amazing is that Rosie is obeying the man's Polish commands. Suddenly Jacob knows why the elephant has been so difficult to train.

With Jacob's help, August and Marlena design an elephant act that thrills the crowds. However, shortly after the first show, August accuses Marlena and Jacob of having an affair. A fight breaks out that leaves both Jacob and August injured. Marlena takes the opportunity to leave her husband, no longer able to cope with his odd behavior. Jacob learns at this point that August suffers from paranoid schizophrenia. Not only this, but the circus owner wants August and Marlena to get back together despite August's violent behavior, and the owner wants Jacob to facilitate their reconciliation.

Jacob goes to Marlena and begs her to run away with him. Marlena agrees; however, Jacob has obligations to other members of the circus and cannot leave for several more weeks. Jacob formulates a scheme with the circus boss to keep August away from Marlena under the guise of getting them back together. The plan works for a while until the circus boss begins to figure out Jacob has ulterior motives and formulates a plan of his own. Soon after, Jacob's friends are thrown from the train and killed. Jacob plans to leave that night with Marlena; however, before they can leave, there is a stampede in the big top that kills both the circus boss and August. Jacob and Marlena are free to live their lives uncomplicated. They join the Ringling Brother's Circus and live a happy life until Marlena's death.

Now Jacob is alone in the assisted-living center. His family has forgotten whose turn it was to visit him, and no one has come. Jacob decides he does not have to miss out on the circus that has set up their tent down the street just because his family is too busy. Jacob sneaks out of the center and walks to the circus. Once there, the ticket boy attempts to turn him away, but a kind manager appears and offers Jacob a wheelchair and a free seat. Jacob tells the man that he was once with the circus, and the man is so impressed by Jacob's story that he invites him back to his trailer after the show to learn more. Over drinks, Jacob tells his story for the first time, having held it in all those years for fear of exposing a secret he kept from Marlena. Feeling as though a burden has been lifted, Jacob is filled with new life. Jacob decides that night to run away with the circus once more and live his life like the man he is on the inside rather than the old man people see on the outside.