A young woman named Maggie is smoking on the roof of her apartment. Maggie spends her days taking care of her father, who has pulmonary disease from years of smoking and cannot do simple tasks by himself. Maggie has two sisters, but they both have families of their own and do not  live close by. After helping her father for the day, Maggie returns to the roof in the evening to smoke again. She flicks the butt across the roof without extinguishing it, and it falls between a small storage building and the edge of the roof.
Maggie walks over to check that it did not land on anything flammable. She discovers litter and debris, and a duvet cover that is draped over something in the middle of the litter. She pulls the duvet cover back, and discovers four eggs that are up to her knees. She touches one and feels something inside move. Maggie returns inside, confused at what could have left them there.
The next morning, Maggie smokes a cigarette out of her bedroom window. She sees a figure standing on top of the climbing structure on the playground. The figure looks straight at Maggie, and shuffles to the side and opens a long coat. Maggie makes coffee and takes it up to the roof. She touches the same egg as before, running her hands over it and feeling it. She then tries to pick it up, and she feels something inside squirm which makes her snatch her hands back. She looks over at the park, and sees the same figure. It screams and opens its coat, which is actually wings. Maggie screams, dropping her coffee cup and running inside.
Maggie spends the next few days smoking from the bathroom out of fear, and she has nightmares about crows. She decides to go to the roof again, where the eggs have hatched, except for the one she originally touched. As she looks at the ugly dark birds, Maggie sees a dark shadow in her peripheral vision and screams; it is the mother. Maggie watches as the bird feeds the babies the insides of a motorcyclist's head. Maggie swears, and the bird looks at her. It comes towards her, and she hurries inside and slams the door. 
While she was on the roof, Maggie's father died. She attends his funeral with her sisters, then is living alone at the apartment. Maggie goes up to the roof again. She yells at the birds to stop screeching, but they get louder. She grabs the nearest one and throws it off the roof, and it lands on a car below. She does the same thing with the rest of the birds, until just the unhatched egg is left. She feels the egg, but it is cold. Maggie cracks the egg open, and finds a dead bird inside. She wraps the dead bird in her jacket. She lays her cigarettes on top of the dead bird, then crawls into the nest despite touching some blood. 
When the mother comes back, Maggie tips her head back and opens her mouth. The bird pulls her insides out, which are all black. As the bird rips black organs out from her, the dead bird stirs. When Maggie is empty she collapses, and the baby bird bursts forth from her jacket.