The main character of "Bud, Not Buddy" is 10-year-old Buddy Caldwell, a runaway orphan determined to find his father whom he suspects is Herman E. Calloway. Angela Janet Caldwell, Buddy's mother, dies before the start of the novel, but her presence is felt throughout. Other notable characters are Todd Amos and his parents, whose cruel treatment of Buddy drove him to search for his birth father.
"Bud, Not Buddy" is a coming of age story about an orphaned African-American boy searching for his family during the Great Depression. As Bud travels to the Grand Rapids to meet Herman, he encounters a rich and varied cast of characters, Each of whom affects him in some way. Bugs, a fellow orphan, swears to be brothers with Bud but gets left behind when the two attempt to board a train. Bud also experiences his first taste of what a real family looks like when he meets Lefty Lewis and his daughter and grandchildren, who feed and clothe Bud on his journey to Grand Rapids. Bud is moved by their displays of kindness and compassion. Bud also finds some romance during his journey in the form of Deza Malone, a young girl who kisses him and promises to meet him again.