Ten years ago, an impossible thing happened: A flock of pigeons picked up a human baby who had been abandoned in an empty lot and carried her, bundled in blankets, to their roof. Coo has lived her entire life on the rooftop with the pigeons who saved her. It’s the only home she’s ever known. But then, a hungry hawk nearly kills Burr, the pigeon she loves most, and leaves him gravely hurt. Coo must make a perilous trip to the ground for the first time to find Tully, a retired postal worker who occasionally feeds Coo’s flock and who can heal injured birds.