A lightning bolt strikes young Lucy Callahan and turns her into a compulsive math genius in 2018’s The Miscalculations of Lightning Girl by Stacy McAnulty. The novel, for middle-grade readers, traces Lucy’s struggles as she emerges, after years of home schooling, to attend public school and deal with the friendships, problems, and betrayals she encounters as a young person with both a brilliant mind and obsessive-compulsive disorder (OCD).

Award-winning author McAnulty has written many books for early readers, including the Dino Files series, plus multiple novels for middle-grade readers. The Miscalculations of Lightning Girl appears on seven best-of books lists for young people.

The ebook version of the 2018 first edition forms the basis for this study guide.

Plot Summary

During a thunderstorm when she’s eight, Lucy gets struck by lightning. She survives, but suddenly she’s a genius who can do complex math problems in her head. She lives with her grandmother, Nana (Barb Callahan), who must pull Lucy from second grade because she’s obsessed by numbers, counts everything, has to sit three times every time she gets seated, is afraid of germs, and can’t get along with the other kids. Nana homeschools her, and by age 12 Lucy has her GED and is ready for college studies.

Nana thinks Lucy needs to learn more about socializing, so she puts Lucy into the seventh grade at the neighborhood middle school. Lucy hates it: She already knows all the lesson materials, and the other students quickly decide she’s different because of her strange habits. She enjoys math class but hides her math ability. She makes a friend, Windy Sitton, who’s a bit pushy; however, she’s smart, fun, and doesn’t care about Lucy’s OCD. They visit each other’s homes, discover a mutual love for junk food, paint their nails, and watch movies on TV.

The school wants the kids to form small groups and do community projects. Windy teams with Lucy; for a third member, they make do with Levi, a sullen boy who already got Lucy in trouble when he copied her math test answers. They decide to volunteer at a pet shelter. Lucy dislikes dogs, but one is named Cutie Pi—Lucy loves the number pi—and the dog has a lightning-bolt mark on its fur, so Lucy decides to help the shelter catch up on its paperwork.

With help from Levi, she enters the data into a computer and does a statistical survey of the shelter’s adoption history. Cutie Pi takes to Lucy, and she finally pets him, the first time she’s touched a dog. She also confesses to Levi about her math abilities; he’s impressed and promises to keep her genius a secret.

In social studies class, the teacher, Ms. Fleming, tries to make Lucy read a passage, but she can’t until she first counts up all the words. She tries to beg off, but the teacher insists until Windy and Levi defend her and accuse Ms. Fleming of bullying her. The teacher kicks all three out of class, but Lucy appreciates their sacrifice and realizes that being friends demands from her a higher standard of commitment.

Using Lucy’s statistics, the team chooses the dogs that need the most help getting adopted. Levi photographs them, and they publicize them online. Dogs that normally take weeks to find a home get snapped up in a day; it’s a great success. Lucy learns, though, that her favorite, Cutie Pi, has brain cancer. She persuades the shelter to offer the dog for free, and the team publicizes Cutie Pi’s plight, hoping someone will want to care for the dog in his last year.

Math teacher Mr. Stoker, suspecting that Lucy is holding back, gives her a math problem she can’t solve instantly. It’s from the most famous college math contest in America, and he doesn’t yet have the answer himself. Intrigued, she finally figures it out but doesn’t tell Mr. Stoker.

Nana learns of a high school for bright math and science students. She and Lucy’s beloved Uncle Paul drive Lucy there for a visit. She takes the admission test and earns a perfect score. The academy wants her, but Lucy has mixed feelings: She just got used to one school and made new friends there.

On Halloween, Lucy confesses her math prowess to Windy and makes her swear not to tell anyone. Later, at Windy’s overnight party at a water park, cruel Maddie Thornton edges Lucy aside and monopolizes Windy’s time. Lucy overhears Maddie make fun of her while Windy defends Lucy by revealing her math genius. Upset that Windy betrayed her, and angry when Maddie asks Mr. Stoker to remove Lucy from math class, she confronts Maddie, then leaves school, intending never to return.

On impulse, she walks through a bad part of town on her way to the pet shelter. She gets lost and calls Levi, who helps her find her way. At the shelter, Lucy learns Cutie Pi will be taken the next day by animal control and euthanized. Lucy begs Nana to bring the dog home, and Nana agrees, but for one night only. Windy visits them at home and begs forgiveness from Lucy; they become friends again. Levi arrives, and all of them phone everyone they know, searching for someone who’ll adopt the stricken dog. Lucy posts a plea on her favorite math forum online.

The next morning, Lucy and Nana drive Cutie Pi to the animal control office. Windy and Levi arrive to help Lucy say goodbye to the dog. Mr. Stoker also shows up: He read Lucy’s math-forum post, and he wants to adopt Cutie Pi.

Lucy apologizes to Maddie for her outburst, but Maddie gets herself transferred out of Mr. Stoker’s class, and the two girls never talk again. As Levi predicts, the students get over their amazement about Lucy’s genius. Mr. Stoker gives her challenging math puzzles, and she even reads a poem aloud in Ms. Fleming’s class. Without having to calculate anything, Lucy finds her life becoming happily typical.