In the oppressive heat of August in rural Osage County, Oklahoma, the Weston family's dysfunctional dynamics begin to unravel following the disappearance of their patriarch, Beverly Weston. His wife Violet, who is battling mouth cancer and addiction to painkillers, is left to face the crisis with her three adult daughters—Barbara, Ivy, and Karen—each who harbors her own deep-seated issues and resentments. The family is forced to reunite under the roof of the old homestead, where long-simmering tensions are reignited.

The escalation of family conflict is inevitable as deeply buried secrets come to light amidst the chaos of their patriarch's absence. Barbara, the eldest daughter, struggles to assume the role of the family's anchor while dealing with her own crumbling marriage. Ivy, the middle daughter, wants to find her own path but feels tethered by family duty. Karen, the youngest, arrives with a new fiancé in tow, seemingly oblivious to the underlying turmoil. The interactions among the sisters, their mother, and other relatives expose a tangled web of past grievances, deceptions, and psychological trauma, turning the family gathering into an explosive confrontation where nothing is off-limits.