After her more popular twin sister, Aida, goes missing in their small, safe, suburban town one month after their sixteenth birthday, a woman holds on to hope that she'll be found. The detective asks if Aida wanted to run away and the woman doesn't divulge that she and Aida had a runaway fund in a secret box as kids. Aida went missing when she was meant to meet the woman after they both got off work and never showed up. The woman's parents are two intellectuals who had children late and fell out of love. Her mother wanted the twins to lean into their connection, while her father wanted them to learn how to live their own lives. The two were inseparable. When their parents would fight, the woman would comfort their father and Aida would comfort their mother. There are sightings of Aida around town, but it's just people seeing the woman, because the two are identical. At one house party their parents threw, Aida had had her first kiss with their mother's friend's son, a college drop out named Marlon. After she disappears, their mother—who stops leaving the house, certain Aida will come home—becomes convinced Marlon abducted her, even though he has an alibi. The woman reflects on their parents' crumbling marriage and their father's affair with one of his college students and disclosure to the woman that he no longer loved their mother. Aida's torn shirt is found in some bushes near the high school parking lot. The woman starts homeschooling in the fall, not going back to school or to work. The family get a bunch of tips that seem like false hope of sightings of Aida. Then, a hiker finds Aida's months-old boots. The woman's father finds resolution through giving up hope, while her mother clings onto it. Then, some teenagers find Aida's skull in the mountains. A few days before, the woman had imagined the wind as Aida calling her name.