A professional cellist known as Tiny dreams of making love with a female owl and discovers she is pregnant. She lives in Sacramento with her husband, a tall intellectual property lawyer, and when she tells him the news, he reacts with exuberant joy. Tiny is far less certain. She tries to explain that the baby is an "owl-baby," conceived not by him but by her owl-lover, a woman from a wild place called "the gloaming." Her husband dismisses these claims as hormonal jitters, and when Tiny insists the baby will kill her, he hurls a deck of cards across the room and refuses to engage.
The owl-baby asserts itself from inside the womb, disrupting Tiny's cello playing and flooding her thoughts with mysterious chitterings. She drives to a women's clinic, but the counselor tells her the decision is hers alone. A childhood memory surfaces: Her father once took her to a zoo where a giant owl-like creature called a Strix was caged. She felt kinship with it and screamed; her father and the zookeeper beat her. Her mother fought back and fled with Tiny into the gloaming, a wild borderland beyond their neighborhood, where her mother's body transformed into a tree. Tiny continued alone until a maternal figure called the Bird of the Wood found her and took her home.
At her husband's family gatherings, Tiny is an outsider. He is the youngest and shortest of six competitive brothers. His domineering mother raises rescue birds on a barren former orchard but subtly mistreats them. One sister-in-law, whom Tiny privately calls the "secret aborter," confides about a past abortion. Tiny's string quartet rehearsals collapse as the owl-baby causes blood blisters that make it impossible for her to play.
Tiny flies to Berlin to contemplate her future. Her owl-lover appears in a restaurant, enormous and rank-smelling, begging Tiny to return to the gloaming. Tiny refuses. On the flight home, the owl-baby grips her from inside, pleading to be loved. Tiny surrenders: She will be a mother. Her husband meets her at the airport and they commit to having the baby together. Back home, her quartet replaces her and she steps away from music entirely. Her scent turns gamey and wild, repelling everyone around her; her husband moves into an apartment above their detached garage.
Tiny goes into premature labor while her husband is at a conference in Sydney. The delivering doctor notes a tufted head, yellow eyes, chitinous scaling, and ambiguous genitals consistent with Strigiformes, the order of birds that includes owls. In a dream, the Bird of the Wood asks Tiny whether she is prepared to be the baby's mother: If she says no, the baby will die; if yes, the baby will probably kill her. Tiny names the baby Chouette, after hearing an aria from Massenet's opera
Werther, though everyone will mistakenly call her Charlotte. Her mother-in-law tries to prevent Tiny from taking the baby, but because Tiny listed "Owl" as the other parent on the birth certificate and omitted her husband's name, she has sole legal authority. She takes Chouette home.
Early motherhood is grueling. When Chouette's hardening beak makes breastfeeding impossible, Tiny discovers the baby thrives on raw meat, progressing from cube steak to frozen newborn mice ordered online. Her husband arrives from Sydney, sees Chouette, and collapses in grief. He begins hoping she will die, telling callers not to visit. Tiny makes her choice: Chouette will be the one she loves most, because no one else ever will.
Left behind during the family's Annual Summer Barbecue, Tiny notices Chouette tapping her egg tooth rhythmically on the crib bars. She convinces her husband to order a small marimba, and Chouette plays it with her egg tooth, producing dissonant notes outside the Western scale. Mother and daughter begin afternoon music sessions, finding a tentative common language. The secret aborter visits, leaves gifts, and becomes Tiny's "secret friend." Chouette makes her first kill: a neighbor child's pet gerbil, swallowed before anyone sees.
Her husband launches a campaign to normalize Chouette through therapy dogs, swim therapy, special schools, and behavioral treatment, each intervention ending in disaster. In retaliation, Chouette destroys Tiny's cello and her own marimba, ending their music-making permanently. Tiny and the secret aborter begin a love affair that restores Tiny's confidence. She starts taking Chouette on nighttime hunts beyond the paved roads. The affair ends when the secret lover announces she is pregnant. Before she can leave, Chouette wakes, breaks free, and slashes the woman's abdomen. The secret lover survives and tells no one the truth.
On a later hunt, Chouette becomes trapped in a nylon bird-net. Both return home bloody, and Tiny is hospitalized on painkillers. Her husband seizes the opportunity to take Chouette to a treatment center in Malibu. When Tiny wakes, Chouette sits rigidly in her father's lap, a chrome skullcap covering her head. Two holes have been drilled in her skull and a "language-approximation device" filled with synthetic intelligence has been implanted. Chouette now speaks in scripted phrases: "My mother is so supportive" and "My father is really handsome."
Tiny discovers that submerging Chouette in water temporarily shorts out the device, restoring her owl-self. She begins giving Chouette therapeutic baths when unsupervised, but the transformation deepens: Chouette eats puréed food, chats with her grandmother by phone, and refuses nighttime hunts.
Tiny's husband takes Chouette to the Annual Summer Barbecue for the first time. Only Tiny's father-in-law, who now has dementia, embraces the child, telling Tiny, "There is nothing wrong with your girl." He throws Chouette into the pool, as he once did with his own sons, and Tiny leaps in after her. The submersion shorts out the device, and Chouette reverts to her owl-self. When Tiny's husband reaches for Chouette, the child gouges out his right eye and eats it, a strike hidden by the fluttering rescue birds. Her grandmother, blaming the birds, chops them up with an axe. Before Tiny's husband returns from the hospital, the owl-lover emerges from inside Tiny's chest to warn her that Chouette is in danger and to urge Tiny to trust her own strength.
Her husband returns wearing an eye patch and tells Tiny she must be institutionalized. Tiny refuses. In a passage the narrator frames with deliberate ambiguity, Tiny describes killing her husband, his mother, and the day nurse. She flees with Chouette.
They travel by truck and bus through a succession of towns. On a final bus ride through a violent storm, Chouette begins to grow, filling Tiny's lap, then the seat, then the entire bus. She tears open the roof and rises to monstrous, magnificent proportions, then tells Tiny she is not going to feast upon her liver but is going to leave her. Chouette flies away without looking back, and the bond between them snaps.
Tiny rages at the empty sky, feeling she gave up everything for toil, blood, and excrement. But small birds return after the storm, singing in thanksgiving. Their chorus shifts Tiny from grief to fragile hope. The rain stops, the air smells fresh, and Tiny holds her head high. She does not know whether a bus will come for her, but she begins to feel that it is her turn to choose something for herself.