Fifteen-year-old Astrid Magnussen finds herself navigating life in Los Angeles alongside her free-spirited artist mother, Ingrid. With no memories of her father, Astrid heavily leans on her self-absorbed mother for support. When Ingrid's relationship with the writer Barry crumbles due to infidelity, she takes a dark turn by ending Barry's life using white oleander poison and is subsequently imprisoned. This tragic turn of events leaves Astrid under the guardianship of social services.
Astrid's first foster mother is Starr Thomas, a recovering alcoholic and former stripper who has found solace in her faith. The duo initially bonds well, even leading to Astrid's baptism into Starr's church. However, when Ingrid learns of their connection, she creates tension, spurring Astrid to take a stand. Starr’s jealousy over Astrid's perceived relationship with her boyfriend Ray drives her back to drinking, culminating in a violent encounter where Starr, in a drunken frenzy, injures Astrid by shooting her in the shoulder. Protecting Starr, the children convince Astrid to remain silent about the incident.
After healing in the hospital, Astrid is transferred to McKinney Children's Center (also known as "Mac"). There, she experiences conflict with some of the other girls but eventually finds a friend in fellow artist Paul Trout. Her journey continues when she is placed with a former actress, Claire Richards, and her producer husband Mark. The fragile yet caring Claire quickly forms a close bond with Astrid, who seems to flourish under her care. However, when Astrid learns that Ingrid has been writing to Claire, she insists on a prison visit. Unfortunately, Ingrid's manipulative nature exacerbates Claire's insecurities regarding Mark, leading to Claire's tragic suicide. This heartbreaking event deeply impacts Astrid, who feels betrayed by Ingrid.
Astrid telegraphs her grief to Ingrid about Claire's death and opts not to visit her again, returning to Mac. Conflicted, Paul reveals his imminent move to New York and invites Astrid to join him, but she coldly declines. As she continues to navigate foster care, Astrid finds herself in the care of Rena Gruschenka, a Russian immigrant who exploits the foster children for her business, further hardening Astrid's demeanor. Rena encourages Astrid to take advantage of an offer from Susan Vallares, Ingrid's attorney, to testify falsely for her mother in court. Despite Rena's temptations, Astrid refuses to compromise her integrity.
In an unexpected twist, Astrid pays Ingrid a visit in prison, where she exerts newfound control, demanding the truth about her family history in exchange for testifying that Barry took his own life. The confrontation reveals deep-seated issues about her father, Claire, and a mysterious figure from her past named Annie. As time passes, she and Paul rekindle their relationship, and he attends her mother's trial as Astrid prepares to give testimony. However, things take a turn when she finds out that Ingrid has instructed her attorney to ignore her statements, leading to a painful goodbye as she watches her mother being taken away once again.
Fast forward two years, a transformed Astrid now resides in New York City with Paul, focusing on her art. She creates thought-provoking dioramas in suitcases, narrating the tumultuous chapters of her life. With each suitcase she closes, she pledges never to revisit the torment within. Pausing at the final suitcase that symbolizes her relationship with Ingrid, she reflects on a bittersweet truth: despite her flaws, she recognizes that her mother loves her in her own complicated way.
