As a young girl, Jeannette Walls finds herself living a peripatetic lifestyle alongside her artistic mother, Rose, her brilliant yet reckless father, Rex, her older sister, Lori, and her younger brother, Brian. One day, while attempting to cook alone, Jeannette suffers severe burns. During her hospital stay, a doctor and social worker express concern about her home life, but Rex cleverly diverts their attention and sneaks Jeannette away. The family sets off again, with Rex's whimsical dreams of building a glass castle captivating Jeannette's imagination.
Eventually, the family grows to include infant Maureen, leading them to a series of transient living situations, ultimately settling in a rundown house in Utah. There, Jeannette undergoes a harrowing experience when Rex drunkenly attempts to teach her how to swim, nearly drowning her in the process. After Rex assaults a lifeguard, the family finds themselves on the run, heading to Welch, West Virginia, where the children meet their grandparents and uncle, Stanley. Living in a crumbling home deep in the woods, the Walls family faces extreme deprivation, lacking basic necessities like water, gas, and electricity. When hunger strikes, Rex foolishly spends their last money on alcohol instead of food.
Jeannette, resolute and filled with compassion, stitches up Rex's injuries after he returns home intoxicated. She implores him to quit drinking, leading Rex to tie himself to his bed in a determination to detox. Against the odds, he secures a job in construction and the family enjoys a rare Christmas filled with joy. However, when Rose and Rex journey to Texas for a family funeral, the children's traumatic experiences resurface. After witnessing a terrible act against Brian orchestrated by Irma, the sisters throw themselves into action, but their attempts to protect Brian are thwarted by Stanley. Rex's refusal to believe his children's plight catalyzes a reluctant return to drinking, resulting in tumultuous fights with Rose.
As Jeannette matures, she is drawn to journalism, ultimately leading to financial independence. The siblings work diligently to fund Lori's move to New York City, causing tensions to escalate with Rex. During a visit home for a funeral, Jeannette is dragged into one of her father's schemes, where she narrowly escapes an attempted assault by Robbie, Rex's acquaintance. Crestfallen upon discovering that her father has pilfered her savings, Jeannette makes a desperate exit. Her journey continues as she enrolls in college in New York City, where financial struggles loom large, only to be uplifted by a surprise visit from Rex, bearing gambling winnings and wild dreams for her future.
By 1989, Jeannette has risen to the ranks of a gossip columnist for New York Magazine, engaged to a financial analyst named David. Yet, during a dinner with one of David’s clients, Jeannette fabricates stories about her parents. On her journey home, she’s confronted with the stark reality of her now homeless parents scavenging for food. A family visit reveals how the lives of Brian and Lori have progressed, while Maureen continues to inhabit the chaotic lifestyle with their parents. Friction mounts when Rex and David’s drunken antics lead to a violent altercation.
The unraveling ties of family continue as Maureen decides to relocate to California, leaving Jeannette feeling increasingly burdened by her ties to her past. During her engagement party, she discovers that her family has possessed potentially valuable land without ever acting on it. Infuriated, Jeannette cuts ties with Rex before he nears his end. Despite receiving a call from Rose about Rex's terminal condition, she initially shuns the idea of reuniting. However, at a dinner event, she musters the courage to confront the painful truths of her upbringing, finally racing to find Rex. Their reconciliation brings closure before his passing.
Years later, Jeannette, now a freelance writer forging her path alone, carves out a new Thanksgiving tradition with her siblings, reflecting on the irrepressible and idiosyncratic legacy of their father.
