Set in rural Sault Ste. Marie in Michigan's Upper Peninsula, the novel opens with Everett Lindt, a sheep farmer, walking the fields his family has worked for generations. He speaks to the ghosts of his ancestors about his wife, his daughter, and his farm, but mostly about a girl named Mary and the nine months they spent together. He says the Lindts who came before him are the only ones he can tell what happened.
The story moves back to the summer of 1995, when Everett is seventeen and about to start his senior year. He bales hay with his best friend, Charlie King, the charismatic son of local hog farmers. One day, Kylie Mason, the daughter of the landowner they hay for, brings lunch to the field with Mary Williams, a newcomer who has just moved into a modular home on the property. Mary is a Coast Guard kid who has lived in Puerto Rico, Massachusetts, Florida, and Buffalo, New York. She is artistic, sharp-tongued, and determined to leave after graduation. Everett is immediately drawn to her, but when he calls, she politely declines, saying she wants to focus on school.
That summer revolves around the Chippewa County Fair, where young people in 4-H, a youth agricultural organization, exhibit and auction the lambs they have raised. Everett's seven-year-old sister, Katie, is showing Fluffernutter (Fluff), a bottle lamb she raised after its mother rejected it. Everett places a disappointing third in his class, outshone by expensive lambs from out-of-state breeders. He convinces his father, Robert, to let him buy his own ram, breed a group of yearling ewes (one-year-old females), and sell the lambs. On sale day, when Katie freezes at the auction ring entrance, Everett impulsively bids on Fluff with his entire savings of one thousand dollars. Robert is furious, but Everett secures Fluff for breeding.
That night at the fair, Everett dances with Stacy Harris, the fair queen, but the encounter fizzles. Afterward, he finds Mary sitting alone outside a barn, abandoned by Charlie and Kylie, and drives her home. She smiles and says his name the way only she does, stretching it into three syllables.
When school starts, Everett's truck breaks down, forcing him onto the school bus, where he discovers Mary rides the same route. They begin sitting together daily, and a quiet intimacy takes root. Mary tells him about her divorced parents, her absent mother in Florida, and her ambition to attend art school. She shares a fortune cookie saying on her backpack about keeping a green tree in your heart so a singing bird will come. Everett asks to pick her up once his truck is fixed and to show her the farm. She says yes.
Everett shows Mary the ram he purchased at a sale south of the Mackinac Bridge, a late-born Hampshire lamb that Katie names Roman. He takes her to the gully where he and Katie hunt for claybabies, smooth clay formations deposited by ancient glaciers. Mary finds one shaped like a songbird. At Whitefish Bay on Lake Superior, they share their first kiss and become a couple.
One morning, coyotes maul Fluff, who had been slowed by an injury from the herd's oldest ewe, Caroline. Robert hands Everett the rifle. Everett shoots Fluff and buries her. Katie demands to see the body. When Everett tries to cover the damage with a blanket, Katie pulls it off, screams that he is a liar, and runs away.
As fall deepens, Everett and Mary grow closer. They exchange verbal love notes that Mary pretends to seal in a blue Ball jar she finds in the abandoned Bonner barn. In its hayloft, they have sex for the first time. Mary tells Everett she was drawn to him because he kept showing up; for someone whose parents never showed up, that meant everything. She names California as her destination: art school and independence.
Their relationship intensifies through winter. A record snowfall closes school; the Lindt family is snowed in together, warm and close. Everett gives Mary a Queen CD containing "Love of My Life," which she danced ballet to as a child, hoping the music would save her parents' marriage. In her bedroom, Everett asks to remove the condom. Mary agrees reluctantly, then says they should never do it again. It becomes a pattern. On New Year's Eve, Everett tells Mary he loves her. She says it back.
In late March, Mary tells Everett she is three weeks late. She insists on total secrecy. Everett presents a plan: He will work construction and join the road commission. He gives her a cheap ring. Mary flatly agrees. But Charlie reveals that Mary has acceptance letters and scholarships from California art schools. Everett blurts out something Charlie once said about Kylie being just a fling; Kylie, overhearing, dumps food on both of them and storms out. Everett and Charlie fight at their lockers. After school, Everett confronts Mary about the letters. She erupts: She never wanted any of this. She accuses him of trapping her and lifts her sweatshirt to reveal bruises across her belly. She has been hitting herself, trying to end the pregnancy.
That night, a violent storm hits. The rams get out, though the cause remains uncertain. Robert's old ram, Curly, breaks Roman's neck and breeds several ewes. Everett buries Roman next to Fluff. His plans for a new breeding herd are destroyed. His mother, Shauna, sensing his distress, tells him the full story of her own teenage pregnancy: Her father called her a whore, her mother said nothing, and Robert came for her in the middle of the night. She tells Everett he did not ruin her life but revealed it, showing her who the people around her really were.
Everett visits Dr. Cavender, the local veterinarian, about the unwanted pregnancies in the ewes. The vet prescribes Lutalyse, a prostaglandin drug labeled "FOR USE IN ANIMALS ONLY" that destroys the hormonal structure sustaining pregnancy and causes the uterus to contract. Everett takes the vials home and calls Mary.
At Rotary Island, Everett walks Mary through the injection process. She pushes the needle into her thigh. They wait for hours. Nothing happens. Frantic, she injects a second dose. On the drive home, she begins shivering and vomiting. Everett begs to take her to the hospital; she refuses. He carries her inside, lays her in bed, and writes his first and only love note, confessing his love. He places it in the blue Ball jar surrounded by her pelican drawings. She wakes in pain and orders him to leave.
That night, Everett waits by the phone. Mary does not call. He goes to the barn at three in the morning and presses his face into Caroline's fleece. Headlights sweep through the barn. Mary has come in her father's truck, carrying Everett's Carhartt jacket. Inside it is what came out of her body, which Everett describes as half-formed and unfinished, like a claybaby.
They ride the four-wheeler across the moonlit field to Croft's Place, the family's disposal area for dead animals. Everett digs a grave and buries the bundle alongside the ring, next to Roman and Fluff. He breaks down. Mary tells him why she was drawn to him: He is known by this place. The land, the animals, the people all recognize him. She wanted to feel what that was like. She says it felt good to be wanted.
Everett helps Mary into the truck. She touches his hand one last time and drives away. The dawn glows over the St. Marys River. A robin sings. Everett stands alone, telling himself to remember.