Joe is a twelve-year-old boy who lives in absolute luxury after his father invents a wildly successful toilet paper. Despite having his own waterslide, cinema, and immense wealth, he suffers from deep social isolation. As the "billionaire boy," he faces bullying at his elite private school and decides he would rather attend a regular public school in secret to finally make a genuine friend.

Mr. Spud is a former factory worker who became an overnight billionaire by inventing a revolutionary toilet paper called Freshbum. He thoroughly embraces his new status, living in the massive Bumfresh Towers and dressing in outrageous outfits like golden jumpsuits and expensive toupees. He genuinely loves his son but mistakenly believes that spending immense amounts of money is the best way to show affection.

Bob is a twelve-year-old student at the local public school who lives with his widowed mother. He helps out extensively at home because his mother works two jobs to support them. Bullied by his classmates for his weight, Bob proves to be a kind and genuine person who enjoys simple pleasures like sharing Twix bars with a friend.

Lauren is a new student at Joe's public school who quickly becomes the center of attention. She is confident, assertive, and displays martial arts skills when confronted by local bullies. She spends time with Joe, laughing at his jokes and sharing lunches, making him feel noticed and appreciated at school.

Miss Spite is a highly strict and terrifying history teacher at Joe's new public school. Nicknamed "the witch" by her students, she is infamous for her grumpy attitude and merciless approach to discipline. She hands out harsh punishments like litter duty for minor infractions, refusing to give anyone special treatment.

Mr. Dust is the principal at the school Joe and Bob attend. Nearly one hundred years old, he walks so slowly that the students have nicknamed him "the tortoise." Despite his frail appearance, he maintains authority over the school's eccentric staff.

Mrs. Trafe is the cheerful but untalented cook at the school cafeteria. She creates unappetizing dishes like "gerbils on toast" and "macaroni snot," ensuring the dining hall is usually empty enough to serve as a safe haven from bullies. She acts as a friendly ear for students but often complains about needing expensive hip surgery.

Raj is the friendly and enthusiastic owner of the local corner store. He loves selling sweets and striking up conversations with the neighborhood children. He is perceptive and welcoming, offering the kids a safe place to hang out and read the newspaper while they buy their snacks.

Sapphire is Mr. Spud's nineteen-year-old girlfriend. She wears heavy makeup, fake fingernails, and spray tan. She frequently makes outrageous demands for presents, such as a private jet or a bucket of diamonds, and shows little actual interest in Mr. Spud's life or family.

Sue Grubb is one half of the notoriously cruel Grubb twins who terrorize the local public school. She and her brother are completely indistinguishable from each other, both sporting short hair, angry expressions, and small mustaches. She enjoys targeting vulnerable students and stealing their snacks.

Dave Grubb is the other half of the feared Grubb twins. He relies on physical intimidation to extract money and snacks from other students. Like his sister, he is known for his short hair, mustache, and relentless cruelty toward classmates like Bob.

Bob's mother is a widow who works tirelessly to support her son. She holds down two jobs, working as both a cashier and a cleaner at an old people's home in the evenings. Her hard work means Bob must take on many household chores, establishing a sharp contrast to the Spud family's excessive wealth.

Peter Bread is a new teacher hired at the public school. He struggles to maintain order in the classroom, immediately earning the nickname "Pita Bread" from his unruly students who take advantage of his lack of authority.