In Newbery medalist Louis Sachar’s sci-fi thriller Fuzzy Mud (2015), Tamaya and Marshall cut through the restricted woods behind their school to avoid a bully—but encounter a strange mud that has the potential to destroy nearly all life on Earth. While Marshall struggles with the emotional effects of being bullied, Tamaya develops an unusually aggressive rash from the mud and worries that in protecting Marshall she has gravely injured Chad. Each character faces difficult ethical choices. Sachar’s novel addresses troubling issues, from bullying to scientific responsibility and overpopulation, and explores the themes Facing Environmental Crisis, Overcoming Social Isolation, and Doing the Right Thing.

Fuzzy Mud and was a Junior Library Guild Selection and a Financial Times Best Book of the Year. The middle grade novel received a starred review from Booklist and accolades from VOYA and School Library Journal.

This guide refers to the 2015 Yearling edition.

Plot Summary

Fifth grader Tamaya Dhilwaddi lives in the town of Heath Cliff in western Pennsylvania with her mother and attends the prestigious Woodridge Academy on a scholarship. Her parents are divorced, and Tamaya feels that she misses out on things when she leaves to visit her father. A conscientious student, she believes in the school motto emblazoned on her uniform sweater: “Virtue and Valor.” Her friends Monica, Hope, and Summer think Tamaya is too “goody-goody.” She walks to school with seventh grader Marshall, her neighbor, and considers him a friend, though Marshall has recently been bad-tempered.

Chad Hilligas causes Marshall’s irritability. Kicked out of his previous schools, Woodridge is Chad’s last stop before juvenile detention. He’s tough, intimidating, and full of stories about his dodgy exploits. Chad unites the other students against Marshall, so he loses all his old friends—and his self-confidence. When Chad wants to fight him after school, Marshall decides to walk home through the off-limits woods to avoid him. Tamaya faces a difficult choice and either way is forced to break a rule: Disobey her mother and walk home alone, or follow Marshall through the forbidden woods. She fearfully goes with Marshall.

The two friends get lost, and Tamaya discovers a strange puddle of mud with a yellowish fuzz hovering over it. Chad finds them. He beats up Marshall and threatens Tamaya. Desperate, Tamaya grabs a handful of mud and shoves it in Chad’s face. Tamaya and Marshall run home, and she agonizes over the hole in her sweater and Marshall’s insistence that they not tell anyone what happened. Tamaya develops a small, tingly rash on the hand that grabbed the mud. The first of many exponential equations appears: 2 x 1 = 2.

Interspersed with Tamaya and Marshall’s story are flashbacks to US Senate hearings—excerpts from a secret investigation by the Committee on Energy and the Environment a year earlier. Senators focus on SunRay Farm, an experimental laboratory that produces Biolene, a new clean energy source designed to replace gasoline. Their interviewees include Jonathan Fitzman, the eccentric and energetic creator of new microorganisms called ergonyms. These living “ergies,” which double in number every 36 minutes, power Biolene. Fitzman is proud and confident about his creation and insists that the ergonyms are safe because they die when they contact oxygen. A professor testifies that accidents are inevitable with Biolene—and that it won’t solve the world’s overpopulation issue anyway. The products of the equations at the ends of chapters continue to increase.

Tamaya’s rash worsens, developing bloody blisters. She suspects the mud is the cause. Chad isn’t at school, and the headmistress, Mrs. Thaxton, announces that he’s missing. Marshall lies when asked what he knows about Chad. Tamaya realizes it’s her fault for putting mud in Chad’s face and knows he must be suffering. She begs Marshall to tell the truth, but he refuses because after one day without Chad, Marshall has his friends back. He forbids Tamaya from telling anyone. She again breaks the rules, leaving school on her own and returning to the woods to help Chad. The school goes on lockdown when Mrs. Thaxton realizes Tamaya is missing, but Marshall escapes into the woods.

Tamaya struggles through the woods, stepping in more mud. She finds Chad, who is essentially blind; his face is swollen with rash and blisters. Chad feels that no one cares about him. Tamaya leads Chad back the way she came, but she falls in a muddy gully, getting mud in her face and eyes. Marshall realizes that Tamaya is in trouble and finds them both just in time. He goads Chad into helping him pull Tamaya from the mud. Chad apologizes for bullying Marshall, revealing that he resented Marshall because while Marshall’s parents love him, Chad’s parents dislike Chad. Tamaya loses her vision. A search party with rescue dogs finds the kids and takes them to the hospital.

Three months later, additional Senate hearings reveal that Fitzman’s ergonyms have mutated to survive in oxygen despite his safeguards. Fitzman apologizes, as he never intended to create an epidemic. The city of Heath Cliff is quarantined as thousands become infected and sick—including animals. Isolated in the hospital, Tamaya vows to live life with grace even if she doesn’t recover. The rash has no cure until a veterinarian, Dr. Crumbly, discovers that turtles are immune to the ergonyms. Tamaya and others receive a turtle enzyme and begin to heal.

Snow falls, and the Centers for Disease Control announces that extreme cold kills the “frankengerms.” The epidemic is over. The disease is named after Tamaya: the Dhilwaddi Blister Rash. Fitzman, now rich, sends Tamaya a new sweater. Tamaya, Marshall, and Chad become good friends, and Chad takes Tamaya and Marshall to climb trees in the woods, something Chad loves. Tamaya testifies before the Senate Committee, which praises her bravery. Hoping to assuage the environmental impact of the world’s increasing population, the Senate Committee votes to continue producing Biolene now that new safeguards are in place to contain the ergonyms.