Ghost opens with the novel's 12-year-old narrator and protagonist, Castle "Ghost" Cranshaw, discussing some of his favorite world records with Mr. Charles, who runs the local convenience store. Castle buys his usual bag of sunflower seeds and goes to the running track to eat them while watching other middle schoolers run.
Castle comments that he acquired his love of sunflower seeds from his father, who has been in prison for the last three years. He explains that his father was an alcoholic who would get into fights with Castle's mother. One day, Ma told Castle they had to leave immediately. On their way out of the house, Castle's father fired his handgun in their direction. They sprinted to Mr. Charles's store, taking refuge in the storage room. Castle's father waited for the police on their front steps and received a ten-year sentence. That night taught Castle that he is capable of running very fast.
Annoyed by Lu, a sprinter with a cocky attitude, Castle stops eating seeds to challenge Lu to a race. Even though he doesn't have appropriate running gear, Castle runs equally as fast as Lu for the 100-meter dash. Impressed, Coach Brody invites Castle to join the team, which is called the Defenders. Castle resists, claiming basketball is his sport, but the coach convinces Castle to let him talk about it with Castle's mother. After practice, the coach drives Castle home in his taxi. They run into Ma on the way and she gets in the backseat, skeptical of what this stranger is doing with her son. However, Castle's mother agrees to let Castle join the team as long as the coach makes sure Castle stays out of trouble at school.
The next day at school, Castle punches the bully Brandon Simmons in the face during lunch. Given a one-day suspension, Castle pretends to his principal that Coach Brody is his uncle. The coach picks Castle up and makes him run drills for the rest of the afternoon. During practice, Lu teases Castle for wearing oversized jeans instead of running gear, and Castle teases him for his ostentatious running suit. Castle is exhausted by the end of practice, and trips during a sprint on his laces. Afterward, Patty, a fellow newbie, consoles Castle. Patty explains that Lu also used to be nicknamed Ghost because of his albinism, which means he has no pigment in his skin. That night, Castle cuts his high-top sneakers down to low-tops.
At school the next day, a girl sees Castle's shoes and erupts in laughter. Ashamed, Castle runs from school during the lunch break and goes to Everything Sports, where he tries on a pair of silver running shoes. While the salesperson isn't looking, Castle slips the shoes in his backpack and leaves the store. He runs, expecting police sirens, but no one comes after him. He spends the rest of the school day at Mr. Charles's store, helping with restocking in exchange for Mr. Charles letting him skip school there.
The following Friday, Castle and the other newbies go to dinner with Coach Brody at a Chinese restaurant. Before they can start eating, they each have to tell the others something about themselves that most people don't know. Castle reveals the fact that his father is in prison because he tried to shoot him and his mother. He is relieved to have shared the secret, and he feels happy to be a part of a team.
Castle continues training with the Defenders, gradually improving his skills and endurance. He is excited to receive his uniform, which means he is a confirmed member of the team. However, on the day the coach gives the uniforms out, he reveals to Castle that he knows Castle stole his shoes. As punishment, Castle must sit out practice that day, clean the coach's messing cab, and run in his usual shoes for the week. As they talk through the issue, Castle also learns that Coach Brody grew up on the same block as Castle, and that his father had addiction issues. Despite the adversity the coach faced, he earned a gold medal at the Olympics. After a week of good behavior, the coach brings Castle to the sports store to apologize for his theft. The coach then pays for the shoes, allowing Castle to keep them.
The following Saturday, Castle competes in his first track meet, which sees the Defenders face off against other teams. He is happy to be allowed to run in the 100-meter sprint. However, Castle is shocked to see that Brandon Simmons is also competing in the event for another team. Lu encourages Castle to ignore the bully and focus on their team's success. The novel ends with Castle hearing his family cheer him on from the stands as he waits for the starter's pistol to signal the beginning of the race.
