When Zachary Beaver Came To Town, by Kimberly Willis Holt, is about 13-year old Toby Wilson and his best friend Cal, as they come of age. Toby and Cal are from a small town in Texas, called Antler. Their boring lives change when a circus sideshow act rolls into town with the world’s fattest boy. His name is Zachary Beaver. This book is about how friendship overcomes obstacles and is made stronger.
It costs two dollars to see Zachary Beaver, and Toby and Cal eagerly pay because they’re bored with their small-town life. They think he’ll be gone by the next day, but three days after they pay to see him, they discover his trailer in front of the local Dairy Maid. Their curiosity gets the better of them so they investigate. They learn that Zachary’s partner, Paulie Rankin, has left Zachary. Feeling bad for him, Toby and Cal deliver groceries to the trailer. They hide to try to see Zachary's reaction. Soon after, the local sheriff enlists their help and they go back to the trailer to try to befriend Zachary. Despite their attempts to befriend him, Zachary wants nothing to do with Toby and Cal.
At the same time, Toby is facing other challenges. For one, his mom up and left to go to Nashville and pursue her dreams; she entered a contest to be the next big name in country music and decides not to return to Antler. Additionally, Toby struggles with the fact that Cal’s brother is in Vietnam. His name is Wayne and Toby looks up to him. He becomes frustrated with Cal because when Wayne writes to Cal, Cal doesn’t always write back. To rectify this, Toby decides to write a letter to Wayne, except that he signs Cal’s name and not his own.
As if that is not enough stress for a thirteen-year-old, Toby also has a crush on a girl—and not just any girl, the most beautiful girl in Antler according to Toby. Her name is Scarlett, and she doesn’t even notice Toby beyond acknowledging him as a classmate. Instead, she likes a boy named Juan, who is the son of a local farm hand. One day, Juan fails to attend a family party with her and she breaks up with him. Toby uses this opportunity to get closer to Scarlett, and gives her his mother’s pearls as a token of his affection. Despite this overture, she is still in love with Juan.
Toby’s stress continues to grow; aside from his mother’s abandonment, his disdain for Cal’s unwillingness to write to Wayne, and his unrequited love for Scarlett, he has a summer job mowing Miss Myrtie Mae’s lawn. Miss Myrtie Mae is the local librarian and historian in Antler. Her brother, who is senile, was a judge—and Toby is scared of him. One day, when Toby is about to mow the lawn, the judge throws apples at him. Toby overcomes his fear when he realizes that the judge has mistaken him for his grandfather, and after Toby and the judge play baseball together one afternoon, the judge’s behavior toward Toby improves.
Meanwhile, Cal has not forgotten about Zachary and is determined that he and Toby will befriend him. To that end, Cal decides that they will take Zachary to the drive-in. Zachary enjoys himself. Cal sneaks around Zachary’s trailer and discovers that Zachary’s stories about his travels aren’t all true. Instead, the details of the places he has supposedly visited were learned from a collection of books piled in the back of the trailer. Among the books, Cal also finds a baptism Bible that belonged to Zachary’s mother—but Zachary is not baptized. The sheriff is conducting an investigation into Zachary’s background, and tells Toby and Cal that Zachary’s mother was so fat that her funeral drew media attention.
A darkness settles over Toby’s and Cal’s summer when they learn that Wayne has died. The news shocks Toby and he can’t bring himself to visit Cal or anyone else in Cal’s family. His shock is so severe that he can’t even bear to attend the funeral, and this angers Cal, who subsequently ends his friendship with Toby. Toby’s father steps in though and helps Toby and Cal understand one another and make amends.
Toby and Cal decide to work together to get Zachary baptized. They decide that they’ll baptize him in Gossimer Lake. At first, Zachary doesn’t want to be baptized, but when Toby and Cal reveal how they learned he wasn’t baptized, he agrees to be baptized. The ceremony is a success and when they get back to Zachary’s trailer, they find Sheriff Levi waiting for them. Paulie has been in Paris and has told the sheriff he will return in a few days to reclaim custody of Zachary. Throughout these events, Toby helps Scarlett and Juan get back together. He also plans to visit his mother in Nashville. Zachary leaves Antler, but not before promising to write to Toby and Cal, though Toby doesn’t believe Zachary will. Despite that, Toby learns a lot over the summer, including how to see Antler and its residents in a new light.