In the summer of his fifteenth year, Wil Neuton's life is upended when his father, Jim, announces a promotion to district administrator for the state highway department. The family must move from Madison, Wisconsin, to the rural Pinewood area in the north. Wil, fourteen and tall for his age at six feet two, declares his whole life is going down the toilet. His mother, who remembers Jim's past impulsive schemes, is equally skeptical, but the family drives north and settles into a small state-provided house on a gravel road. The first days are chaotic, with Jim's attempt to fix the bathroom plumbing ending in an explosion of water and cursing.
Wil escapes the chaos by riding his ten-speed bicycle. Passing Sucker Lake, a lake so unimportant it appears on no maps, he stops without knowing why, drawn to a small U-shaped island visible from the swampy shore. He finds an old cedar boat, rows out, and lands. Sitting on a large, flat rock that juts into a small bay, he watches sunfish flash gold beneath his dangling feet. The place feels like home. He rows back knowing he will return.
That evening, Susan, a fifteen-year-old girl from a nearby dairy farm, appears at his driveway. Wil is tongue-tied with shyness, but Susan teases him gently and proposes they bike together. She becomes his closest companion as he settles into the area.
Wil begins returning to the island daily, and his visits grow longer and more intense. He sits in perfect stillness on the lake, experiencing what he calls a "perfect moment." He watches a mother loon and her two chicks so intently he allows a mosquito to drink from his hand. On a later visit he watches a great blue heron hunting frogs, and an overwhelming desire to know more about everything overtakes him. He fills a spiral notebook with descriptions and sketches of the heron, then stands on the rock trying to replicate the bird's curved lines with his own body. For one fleeting second he catches the heron's shape in his reflection on the water. He realizes he could spend a lifetime studying the heron and never fully understand it.
Between island visits, Wil and Susan bike to Pinewood. At the cafe they encounter Ray Bunner, a hulking boy who threatens Wil and drives off. Susan warns that everyone eventually has to fight Ray. Inside, Wil listens to farmers discussing rain, crops, and financial ruin, and realizes he has never thought about the people who grow his food.
Wil gets permission to camp overnight on the island. He overturns the boat to form a shelter, builds a fire pit, and attempts meditation on the flat rock. After long minutes his mind goes blank, and into the silence comes a vivid memory of his dead grandmother. He sees her cooking rolls, pushing a strand of gray hair back with her wrist, showing six-year-old Wil a photo album: a small girl, a beautiful young woman who curled her hair all night for Clarence, the shy young man who became Wil's grandfather, a farm mother, a young man in uniform who did not return from the war. Wil writes about her at length, producing one of several embedded writings that punctuate the novel.
His practice deepens. He studies an anthill, experiments with watercolors, and discovers that painting light gives a flat image dimension. During meditation, his body begins performing tai chi movements unconsciously. He writes in his notebook: "To paint. To write. To know. To be."
Susan visits and reads his grandmother piece, moved to tears. Wil tells her he is not leaving the island and asks her to carry word to his parents that he is safe, knowing that if he returns home they will talk him into staying. Susan agrees and begins bringing him food.
His parents arrive by motorboat, tense and worried. His father demands to know if drugs are involved; his mother asks what they did wrong. When Wil mentions meditating, his father accuses him of joining a cult. They bicker for the first time in Wil's memory and leave without resolution, promising to find professional help.
One midday, the bay goes suddenly still. A massive snapping turtle slides beneath the flat rock and waits. Small sunfish gradually return until one drifts a final fraction of an inch too close. The turtle's head slams forward with stunning violence. Wil reflects that the fish's death began not when the turtle struck but when the fish moved that last quarter of an inch.
Ray Bunner arrives at the island by boat with two other boys. He punches Wil twice, splitting his cheekbone and knocking him flat. When Ray reaches toward Susan, something clicks in Wil's brain. He becomes the turtle: cold, certain, without rage, he drags Ray into the water and holds him under until the others tear him away. Ray crawls out vomiting. Wil sits on the beach dripping blood, horrified by what he has done. That night he writes that the turtle was wrong because he became the turtle, and the violent, unthinking striking was wrong.
His parents return more forcefully. His mother asks if Wil would speak with a professional, and he agrees. Susan pulls back from the island, telling Wil that her feelings for him are changing. She kisses him gently, calls him a good friend, and promises to bring food but will not stay again.
Anne Kelliher, a reporter for the small
Pinewood Caller, arrives at the island. Wil agrees to an interview and cannot stop talking, showing her his notebook, watercolors, and heron movements. She calls the experience "astounding," something everyone wants to do, and Wil gives her permission to publish the story. The next day, the counselor his parents arranged, Charles "Chuck" Weaver, arrives. After Wil insists nothing is wrong, Weaver concludes they are dealing with a "Positive Therapy Approach Requirement," meaning Wil is reacting to there being nothing wrong with his life. He departs, baffled.
Anne's story is picked up by a news wire, and three television crews descend on the island at dawn, calling Wil "The Kid on the Island." He gives them a demonstration so they will leave. Over recent days, Wil has noticed flashes of light on the far shore. Using a cameraman's zoom lens, he identifies the watcher: his father, sitting at the base of a tree with binoculars, face swollen with insect bites, camping there to watch over his son.
After the crews leave, Wil sits on the flat rock and writes two words in his notebook: "MY FATHER." He realizes he wants to understand his father but cannot yet, just as he had to observe the heron and the turtle before he could write about them. He rows across the lake. His father explains that after reading the newspaper article and learning what Wil shared with the reporter but not with his parents, he and Wil's mother decided one of them should come and watch. "I wasn't spying on you," he insists. Wil invites his father to come to the island, and Jim's eyes shine: "I'd like that. Very much."
As Wil rows his father toward the island, his throat thick with all there is still to write, paint, and understand, a final thought arrives, clear as the loon's cry in the moonlight: This will end only when they find a bigger island.