Roy only notices the strange, barefoot running boy because the school bully, Dana Matherson, chooses to squeeze Roy’s head, which forces Roy to look out the window instead of at his comic book. Roy is so curious about the boy that he spends the next week looking for him, but he doesn’t see the boy until the following Friday. But when Roy tries to race off the bus to catch the boy, Dana chokes Roy. Roy punches at Dana, shoves past a blond girl (Beatrice Leep), and pursues the boy onto a golf course until a golf ball hits Roy in the head. Later, though Miss Hennepin, the vice principal, sees the bruises Dana left on Roy’s neck, she maintains that Roy started it (Roy did accidentally break Dana’s nose). She suspends him from the bus and asks him to write Dana an apology letter. Roy’s parents, Mr. Eberhardt and Mrs. Eberhardt, are upset about this. And inexplicably, the next day at school Beatrice tries to intimidate Roy, insisting that he didn’t see a running boy.
At the same time, foreman Curly calls Officer Delinko out to the future site of a Mother Paula’s pancake house to inspect some recent vandalism. While there, Delinko trips in big holes. Curly says owls live in the holes, but there aren’t currently any owls using the burrows. Delinko returns again the following week to find the survey stakes pulled out again and alligators in the portable toilets. When Delinko meets with his captain and sergeant, he offers to patrol the site for free. He just wants to solve the mystery. However, Delinko falls asleep in his car at the site and wakes up to his windows spray painted black. As punishment, Delinko is placed on desk duty.
Deciding he can’t let Beatrice and Dana bully him all year, Roy approaches Beatrice at lunch and tells her that in the future, they should just talk things out. Then, after paying Garrett (whose mom is the guidance counselor) to find Dana’s address, Roy asks his mom to drive him to Dana’s house. He gives Dana the apology letter and takes note of Dana’s broken, bruised nose. Later, Roy sneaks out of his house and rides to the golf course. He enters the trees where he saw the running boy disappear and finds a campsite—and a bag of venomous cottonmouth moccasins with glittery blue tails. The running boy pulls Roy away from the snakes, puts a hood over Roy’s head, and says people call him Mullet Fingers. He walks Roy out of the trees and leaves Roy there, telling him not to come looking for him again.
A few days later, Roy sneaks out of the house with a shoebox just as a storm is rolling in. He goes to Mullet Fingers’s camp, but the boy isn’t there—and when Roy gets back to where he left his bike, it’s gone. He trudges through the rain until Beatrice rides up on his bike and tells him to get on the handlebars. She takes him to a junkyard, where she accepts the shoes in the box and promises to get them to Mullet Fingers, whom she reveals is her stepbrother. Beatrice then bites Roy’s bike tire so he has an excuse for being so late. Roy’s parents have reported him missing by now, and Officer Delinko spots and picks Roy up on his way home.
Over the next few days, Curly fields calls from his boss Chuck Muckle, who’s the vice president of corporate relations at Mother Paula’s. Muckle is incensed that construction hasn’t started yet and threatens to fire Curly if Curly can’t stop the vandal, so Curly hires attack dogs. However, Curly gets to the construction site the morning after the dogs arrive to find the trainer, Kalo, in hysterics: there are cottonmouth moccasins with glittery blue tails on the site, and so Kalo refuses to bring the dogs back.
Roy, meanwhile, is allowed back on the bus, and Dana returns to school. Beatrice defends Roy from Dana on the bus, but when Roy is on his own after school, Dana pulls Roy into a janitor’s closet and tries to suffocate him. But Beatrice again comes to Roy’s rescue—she strips Dana to his underwear and ties him to the flagpole—then insists she needs Roy’s help. Lying that they’re working on a science project together, Beatrice and Roy get Mrs. Eberhardt to give them ground beef and sneak first aid supplies. In an ice cream truck in the junkyard, Mullet Fingers is feverish and is nursing clearly infected dog bites on his arm. He allows Roy and Beatrice to dress his wounds and then the three go to the Mother Paula’s construction site. There, Mullet Fingers explains that the dogs bit him while he was putting snakes through the fence. And he did that because the construction project can’t happen: there are wild burrowing owls living on the site, and they’ll die when the bulldozers bury their burrows. Watching the tiny owls nibble at raw meatballs, Roy understands now.
Mullet Fingers collapses from the fever, so Beatrice and Roy rush him to the emergency room and tell the doctor that Mullet Fingers is Roy. (Mullet Fingers’s mom, Lonna, doesn’t want Mullet Fingers and would send him somewhere terrible if she knew he was in town, so they can’t give his real name.) Beatrice runs home to make her dad, Leon, dinner, leaving Roy alone. When Roy’s parents arrive, Mullet Fingers has already escaped the hospital. Roy tells his dad about the owls and why he lied about Mullet Fingers’s identity. Mr. Eberhardt suggests that Mother Paula’s is probably following all the permitting requirements, but he notes that Roy can check on that at city hall.
Over the weekend, Mullet Fingers takes Roy to a creek and shows him how he got his nickname; he can catch mullet, which are tiny fish, with his bare hands. The boy also implies that he has more hijinks planned for the Mother Paula’s property tonight and invites Roy to join him, but Roy refuses. However, Roy wants to help—so he goes to Dana’s house, moons him to draw him outside, and then lies to Dana that there are cigarettes in the construction trailer on the Mother Paula’s property. As such, Curly has a harrowing weekend: not having attack dogs means that Curly himself has to spend the night on the property, and after battling mice in the trailer, Curly comes face to face with Dana trying to break in. Dana runs away, rattraps snapped to his toes, and Officer Delinko arrests him. Curly spends a blissful night at home, proud of his heroics.
On Monday morning, though, Curly discovers that someone took all the seats from the earthmoving equipment. This enrages Chuck Muckle, who insists that Curly has to keep the site locked down until the groundbreaking ceremony on Wednesday. Kimberly Lou Dixon, an actress and former Miss America contestant who portrays Mother Paula in TV commercials, will be there. Officer Delinko’s superiors are impressed with his work catching Dana. So, even though they all believe on some level that Dana isn’t the vandal, they praise Delinko and assign him to surveille the property overnight with Curly until Wednesday. Delinko decides to test his theory that Dana isn’t the vandal by scaring him with a rubber alligator, which proves to him that Dana isn’t capable of handling live ones. The vandal is still out there.
After doing some research on burrowing owls, Roy visits City Hall and discovers that the Mother Paula’s permits have been checked out—or are missing. He then stops at the construction site, leaves crickets for the owls to eat, and encounters Curly. Roy deduces that Curly indeed knows about the owls, which tells him that Mother Paula’s is in violation of Florida’s building laws. That night, when Officer Delinko is patrolling the property, he trips in an owl burrow and comes face to face with a baby owl in the burrow. Noticing the bulldozers, Delinko realizes that doing his job and catching the vandal will have horrible consequences: the baby owl will no doubt die.
On Tuesday morning, Roy reads in the paper that the groundbreaking ceremony is the next day. That afternoon, in Mr. Ryan’s history class, Roy uses his current events speech to tell his classmates about the owls and his suspicions that Mother Paula’s isn’t following all the rules. He shares that he’s going to the ceremony tomorrow during lunch. Roy also knows from his research that it’s illegal to build where there are active burrows, so he also gives Mullet Fingers a camera and asks him to take pictures of the owls—all they need is proof.
Mr. Eberhardt is happy to write Roy a note giving him permission to leave school and attend the groundbreaking ceremony. Beatrice shows up to school with the camera; Mullet Fingers got pictures—and at lunchtime, it turns out that lots of kids from Trace Middle School got permission to attend the groundbreaking. As far as Chuck Muckle is concerned, things seem to be going well at first. But then, Roy and his classmates begin talking and chanting about the owls, and Roy pulls out the camera. The pictures, though, are unidentifiable, and all hope seems lost—until everyone realizes that Mullet Fingers squeezed himself into an owl burrow last night. Mullet Fingers insists they’ll have to dig him up to start construction, and he also threatens to dump over a bucket of cottonmouth moccasins if anyone approaches him. The snakes are rubber, but both Roy and Officer Delinko play along. Muckle loses his temper, hacks at the snakes, and then tries to hurt Mullet Fingers, but the children—and then Kimberly Lou Dixon—link arms to form a circle around the boy and start to sing.
The next morning, a reporter, Kelly Colfax, knocks on the Eberhardts’ door. Mr. Eberhardt gives Roy a file to give to her; it’s the permits, and the Environmental Impact Statement is missing. Over the next few weeks, Mother Paula’s erupts in scandal. Someone discovers the Environmental Impact Statement and a huge check in a councilman’s golf bag, and Chuck Muckle loses his job. The company ultimately abandons the Coconut Cove project and turns the site into an owl refuge to try to rehab their public image, while Kimberly Lou Dixon cancels her contract with the pancake house and publicly announces her lifetime membership to the Audubon Society.
Mullet Fingers, meanwhile, spends a few days at home, is arrested when he runs away, and then runs away from juvie after manipulating Dana Matherson into helping him. Roy suspects Mullet Fingers is still in the area: when Roy returns to the spot on the creek to try to catch mullet himself, he hears a boy laughing and finds a mullet swimming in one of his shoes.
