It is 1997 in Shaker Heights, the planned suburban community where the Richardson family lives. Mrs. Richardson works as a local reporter, and Mr. Richardson is a lawyer. Their four children—Lexie, Trip, Moody, and Izzy—attend high school. The story begins with the house on fire, and Izzy, whom the others suspect of setting it, has disappeared. The story then shifts to eleven months earlier and reveals all of the events that lead up to the fire.
Mia Warren, an artist in photography, and her daughter, Pearl, move into Mrs. Richardson’s rental property. The Warrens move often as Mia looks for inspiration for her work. This time, however, Mia promises Pearl they will stay. She gets a part-time job at a Chinese restaurant to help pay the bills. One day, Moody rides his bike over to meet them, and he and Pearl, both fifteen, become friends. He introduces her to his family. Pearl begins to spend a great deal of time with the Richardsons. Moody has feelings for Pearl, but she develops a crush on Trip.
To thank Pearl for writing her college application essay, Lexie brings Pearl to a friend’s Halloween party. Everyone at the party is drinking. Pearl spots Trip, but then he disappears. Lexie and her boyfriend Brian leave the party to have sex. Pearl, feeling deserted and a little drunk, calls Moody, who picks her up and takes her home. The next Tuesday, Mrs. Richardson stops by her rental property and offers Mia a part-time job cleaning and cooking at her house, which Mia accepts.
One morning, as Mia cleans the Richardsons’ kitchen, she notes that Izzy is home from school. Izzy was suspended for breaking the music teacher Mrs. Peters’s bow and throwing it in her face. Izzy explains that she behaved this way because Mrs. Peters had picked on a shy Black student. Mia surprises Izzy by asking her what she is going to do about it. Inspired by Mia’s words, several days later Izzy, Moody, and Pearl stick toothpicks into the door locks at school, jamming them shut. Unable to use the teachers’ lounge, Mrs. Peters rushes to the girls’ bathroom but has waited too long and urinates on the floor. The shame and gossip of this event follows Mrs. Peters through to the end of her career. Later, Izzy asks Mia if she can be her assistant, and Mia agrees.
On a field trip to an art museum, Pearl and Moody see a photograph of Mia holding a baby in her arms. They later show Izzy and Lexie. Mia claims not to know about the photograph or the photographer, Pauline Hawthorne. Izzy asks her mother to find out about both. Mrs. Richardson tracks down and phones Anita Rees, the New York art dealer who sold the photograph, but Anita hangs up on her.
The Richardsons attend a birthday party at the McCulloughs’ house for the McCulloughs’ baby, a Chinese infant abandoned at a fire station ten months earlier. They named her Mirabelle, though a note with the baby said her name was May Lin. The McCulloughs, who can’t conceive their own baby, are in the process of adopting Mirabelle. Lexie becomes fascinated with Mirabelle and later tells Mia about her. Mia recalls that Bebe Chow, a young Chinese woman at the restaurant, left her baby at a fire station because she couldn’t care for her. When Mia tells Bebe about Mirabelle, Bebe calls the McCulloughs and goes to their home, but they call the police. Mia advises Bebe to go to the media with her story, and it begins to dominate the news. Lawyer Ed Lim offers to represent Bebe, and Mr. Richardson agrees to help the McCulloughs’ lawyers.
When Mrs. Richardson realizes that Mia informed Bebe about the baby, she decides to investigate Mia. She learns that Pearl was born in San Francisco. Using this lead, Mrs. Richardson discovers that Mia Warren is actually Mia Wright, one of Pauline Hawthorne’s former students in New York. Mia’s parents live in Pennsylvania, and she took her younger brother’s name, Warren, after he died.
Meanwhile, the custody case for May Lin/Mirabelle remains a controversial topic. Bebe is granted visitation rights until the case is settled. Mrs. Richardson feels angry at Mia for stirring up trouble and goes to visit Mia’s parents. Meanwhile, Pearl and Trip begin a secret affair. Lexie discovers she is pregnant with Brian’s baby, and she asks Pearl to come with her to an abortion clinic. At the clinic, Lexie gives her name as Pearl Warren because Mrs. Richardson knows the clinic’s director. At the same time, Mrs. Richardson learns from the Wrights that Mia was a surrogate mother.
The narrative then flashes back to tell Mia’s story. In 1980, Mia Wright takes a photography class in New York taught by Pauline Hawthorne, who becomes her mentor. One day in March, a man on the subway introduces himself as Joseph Ryan. He and his wife cannot have a baby, and they offer Mia $10,000 to carry a baby for them. Needing money for school, Mia accepts their offer and becomes pregnant in September. Her brother Warren disagrees with her decision, and they stop speaking. When Warren dies in a car accident, Mia returns home, where her parents become dismayed about her decision to be a surrogate. Mia takes Warren’s car and drives back to New York. She writes a letter to the Ryans telling them she lost the baby and leaves for San Francisco, where Pearl is born. Mia returns to New York to see Pauline, who is dying, and Pauline takes photos of Mia holding Pearl. Needing money, Mia sends one of the photos to the art dealer, Anita, in New York to sell and eventually begins a life on the road with Pearl.
Mrs. Richardson learns about the Ryans and how they paid Mia’s medical bills. Meanwhile, after Lexie’s abortion, Pearl brings Lexie home, where Mia comforts and cares for Lexie. At the custody hearing, Mrs. McCullough testifies poorly about the McCulloughs’ ability to raise the baby to know about her Chinese culture. Moody discovers Pearl and Trip together at her home, and Lexie breaks up with her boyfriend, Brian. Looking for something to use against Bebe, Mrs. McCullough tells Mrs. Richardson that Bebe may have recently had an abortion. Mrs. Richardson manages to peek at the abortion clinic’s records and sees the name Pearl Warren. She believes that Pearl got pregnant by Moody.
This same day, the judge rules in the McCulloughs’ favor. After the verdict, Bebe goes to Mia’s and cries. When Izzy becomes concerned for Bebe, Mia tells her that people find a way to start over, just as new things grow on scorched earth. Mrs. Richardson goes home and accuses Moody of making Pearl pregnant. Moody replies that it was Trip who was having sex with Pearl, not him. Izzy overhears their conversation from her room.
The next morning, Mrs. Richardson confronts Mia about the Ryans and tells her to move out. Mia calls Pearl out of class and says they are going away. She tells Pearl the circumstances of her birth and explains that Mrs. Richardson has found out. As they pack, Izzy appears at the door. Mia reminds her of what she said about scorching everything to the ground and starting over. Leaving some photographs for the Richardsons, Mia and Pearl go.
Back at home, Izzy argues with Moody because he told their mother about Trip and Pearl, and she confronts Lexie about the abortion. When she goes back to Mia and Pearl’s, she sees that they have gone. The next morning, Izzy pours gasoline on her siblings’ beds, drops a match on Lexie’s, and runs away to find Mia and Pearl.
Their house burned, the Richardsons move into their rental property and find the photographs Mia left, each photo reflecting one of the family members. They later hear that Bebe took her baby from the McCulloughs’ home and boarded a flight to China. In their car, Pearl and Mia wish Izzy was with them. At the same moment, Izzy rides a bus to Pittsburgh to see if the Wrights can lead her to Mia. Mrs. Richardson vows to search for Izzy and make amends.