Ten-year-old Kenny Watson lives in Flint, Michigan with his parents Wilona and Daniel, his older brother Byron, and his younger sister Joey. It’s winter and extremely cold, so everyone huddles together in the house—everyone, that is, except Byron, who is 13 and doesn’t want to touch his family members. The family decides to go to Kenny’s aunt’s house because she has better heating. Daniel sends Byron and Kenny outside to scrape ice off the Brown Bomber, which is what he calls the family’s old, beat-up car.
Kenny hates scraping ice, since Byron always finds ways to make him do all the work. As he scrapes one side of the car, Kenny hears Byron saying his name, but he doesn’t check what his brother’s doing because last time Byron called his name in the cold, he ended up spitting snow right in Kenny’s face. Soon, though, Kenny gives in and looks at his brother—only to discover that Byron’s lips are stuck to the side mirror! Kenny fetches the rest of his family and watches as Wilona frets over Byron. Meanwhile, his father can’t stop making fun of Byron for kissing his own reflection. Kenny, for his part, knows Byron would do terrible things to him if their positions were reversed, but Kenny would never act so cruelly toward Byron. After some time passes, Wilona yanks Byron off the mirror, sending him crying into the house.
At school, kids make fun of Kenny, especially since he’s extremely smart and has one crooked eye. A bully named Larry Dunn picks on him, but only a little bit because he’s afraid of Byron and Byron’s friend, Buphead. Both Byron and Buphead are in the sixth grade, and they rule the school, though they only provide a small amount of protection for Kenny. For this reason, Kenny is very happy when a new kid named Rufus gets on the bus one day. Rufus has a strong southern accent and instantly gets made fun of for saying, “Hiya, y’all!” Kenny hopes Rufus will take attention away from him, but then Rufus starts seeking him out. At first, Kenny doesn’t want to be friends with Rufus, worrying they will attract bullies if they spend time together. But he comes to like hanging out with Rufus, sitting with him every day at lunch and giving him some of his sandwich, since Rufus never has food of his own.
As the school year progresses, Byron gets into trouble time after time. At one point, Larry Dunn steals Kenny’s nice leather gloves and bullies both him and Rufus. Afterwards, Kenny tells Byron what happened, so Byron finds Larry and bullies him. He takes the gloves away and smacks Larry on the side of the head. He then pushes him into a chain-link fence. It’s an extremely cold day, but Kenny notices—as his brother beats up Larry—that Larry is wearing a thin, ripped windbreaker and a t-shirt. He also has holes in his shoes, which makes everyone laugh. Unable to watch, Kenny leaves the crowd, wishing he’d never told Byron what Larry did.
After an incident in which Byron gets a perm, Wilona and Daniel are furious. They’ve forbidden Byron from straightening his hair like this, but he did it anyway. As a punishment, Daniel shaves Byron’s head and then laughs at how silly he looks. And though Kenny and his siblings don’t know what their parents are doing, Daniel and Wilona start acting strange. They have long telephone conversations with Grandma Sands, who lives in Birmingham, Alabama. Wilona spends the next few days drawing out a budget in her notebook while Daniel makes improvements on the Brown Bomber. Finally, when the Brown Bomber looks better than ever, he calls the family outside for a surprise: he has outfitted the car with a “drive-around record player.” Everyone is excited—except, that is, for Wilona, who storms into the house while muttering about finances. Soon enough, though, even she comes back out to sit in the car and listen to music with the rest of the family.
After having fun with the record player, Daniel and Wilona break some news to their children: pretty soon, the family will be driving to Birmingham, Alabama, where they will stay with Grandma Sands for a couple weeks before leaving. Byron, however, will stay in Birmingham with Grandma Sands for the entire summer. If he behaves, he can come back to Flint for the school year. If not, he’ll have to spend the year in Birmingham. Enraged, Byron storms into the house, swearing loudly as he goes.
Byron plans to run away the night before the family leaves, but his parents thwart his plans by making him sleep in their room. He also decides not to say a word for the entire trip, but he breaks his silence before they even pass Detroit. Soon enough, he and his siblings fall fast asleep. Wilona falls asleep, too, and even though she meticulously planned where the family would stop each night, Daniel decides to drive all the way from Flint to Birmingham in one shot. They stop at some rest stops that only have outhouses without the kind of toilets the kids are used to, and Byron is horrified to hear that this is the exact kind of bathroom setup that Grandma Sands has at her house. While peeing in the woods at a rest stop in Tennessee, Byron scares both Kenny and himself by talking about how there are white “rednecks” here who have never seen Black people and who would hang them if they had the chance—a thought that sends both boys running back to the car.
Finally, the Watsons arrive in Birmingham. Kenny has heard all about how strict and scary Grandma Sands is, so he’s surprised to see that she’s so small. Even more surprising, though, is that Byron treats her with respect, calling her “ma’am” and gladly doing whatever she asks him to do. Later, Byron senses that Kenny is disappointed by how quickly he surrendered to Grandma Sands, but he claims that he just doesn’t want to be responsible for accidentally killing her. Kenny, however, thinks Byron is just making excuses and doesn’t want to admit that he’s actually afraid of their grandmother.
A few days later, Kenny, Byron, and Joey go swimming. Grandma Sands tells them to stay away from Collier’s Landing, where there’s a dangerous whirlpool that recently killed a young boy. When the siblings reach the path leading to Collier’s Landing, Kenny tries to convince his brother and sister to come with him to check it out. Joey objects, trying to remind Kenny about what Grandma Sands said, but she can’t remember the word “whirlpool.” Byron jumps in and tricks her into thinking that Grandma Sands was referring to the “Wool Pooh,” who he claims is Winnie the Pooh’s evil twin. According to Byron, the Wool Pooh lurks beneath the water’s surface and then pulls young children into the depths when they get too close. Thinking he has sufficiently scared his siblings out of going to Collier’s Landing, he starts walking in the other direction. But Kenny doesn’t want to leave—he still wants to go to Collier’s Landing and can’t believe that his brother, who always breaks the rules, is passing up the opportunity to have an adventure.
Kenny goes to Collier’s Landing on his own. He passes a sign warning swimmers that six people have died in the water here, but he ignores it. He wades into the water and, at first, nothing seems particularly dangerous. But then the ground drops away and he slips into the water. The whirlpool sweeps him up and pummels him. In his struggle, he thinks he sees an angel reminiscent of his sister Joey, who tries to tell him to swim to the surface—but he can’t. He then thinks he sees the Wool Pooh emerge from the depths and grab him. No matter how hard he tries, he can’t fight off the Wool Pooh, but then Byron appears and drags him out of the water and onto the riverbank, where he holds Kenny upside down as water pours out of his mouth. Byron cries and repeats Kenny’s name over and over, pressing his mouth against his little brother’s head and holding him close.
That Sunday, Joey gets ready to go to Sunday School at a local church. Kenny says goodbye to her and compliments how pretty she looks. Shortly thereafter, everyone in Grandma Sands’s house hears a huge boom. After some initial confusion, they learn that a bomb went off at the church where Joey went to Sunday School. They all rush to the church, where there’s a ton of rubble and groups of distraught Black community members. Kenny pushes his way into the church and looks around. He sees a shoe that looks like Joey’s. It’s buried in the rubble, so he tries to pull it free. As he struggles, he thinks the Wool Pooh is holding onto the shoe, but he manages to rip it free, at which point he sprints home. He thinks Joey died in the church bombing and that he’s holding her shoe, and he wishes he told her about seeing her when he was drowning in the whirlpool. All of a sudden, though, he hears Joey’s voice: she’s standing in front of him! They’re both confused, but she explains that she was too hot in the church, so she went to stand on the porch. While standing outside, she thought she saw Kenny, who started running away. Joey chased him all the way home, but she now realizes that the Kenny she saw was wearing different clothes…
The Watsons drive back to Flint that very night. In the coming weeks, Wilona and Daniel try to figure out how to explain to their children that two racist white men bombed a church full of Black children, ultimately killing four little girls. Daniel and Wilona don’t know what to say about this to their kids. Sometimes they just sit on the couch and cry. Meanwhile, Kenny feels troubled by what he saw that day, so he spends his time hiding behind the couch. The family pets always used to go behind the couch when they were injured or sick and would only come out when they felt better, so Byron used to tell Kenny that there are “magical powers” back there. Now, though, Byron forces his little brother to stop going behind the couch. When Kenny admits that he’s sad because of what he saw at the church, Byron says that his sadness is perfectly understandable. But Kenny feels guilty because he ran away from the Wool Pooh even though he thought the Wool Pooh had Joey. Byron tells Kenny that the Wool Pooh isn’t real and that magical powers don’t exist. He reassures his little brother that everything will be all right, saying that sometimes life is hard but that he can still be happy. Finally feeling better, Kenny thinks his brother is right overall, but wrong about one thing: magical powers really do exist. They might not come in the form of “genies” or “angels,” but they appear in other ways, like in the moment that his father smiles at him, or when his mother dresses him in warm clothes, or when his older brother plays with him.