Ben Cash, his wife Leslie, and their six children live an isolated existence on ten acres in the mountainous
Washington wilderness. They are
left-wing anarchist activists disillusioned by
capitalism and American life, who choose to instill
survivalist skills and left-wing politics and philosophy in their children. They educate them to
think critically, and train them to be physically fit, athletic, and self-reliant without dependence on modern technology. They are raised to coexist with nature, are given unique names, and celebrate
Noam Chomsky's birthday instead of
Christmas. The children are accustomed to reading many forms of college-level literature, and, while showing high aptitude and intelligence beyond their years, they are socially awkward as they have not been socialized with the outside world. Ben has been raising the children on his own while Leslie is hospitalized in
New Mexico for
bipolar disorder, away from her family and near her wealthy elitist parents. She dies by suicide while undergoing treatment, and Ben learns that her father, Jack Bertrang, plans to hold a
Christian burial, despite Leslie being a
philosophical Buddhist who abhorred religion. Ben tries to persuade Jack to honor Leslie's wish to be
cremated, to no avail, and Jack forbids Ben to attend the funeral, threatening to have him arrested if he comes. Ben initially decides not to go and prevents his children from doing so, but then changes his mind, driving his children across the country in a repurposed school bus. The family briefly stays at the home of Ben's sister, Harper. She and her husband try to convince Ben that the children should attend school to receive a conventional education; Ben quizzes Harper's children and his children on various topics, such as the
Bill of Rights, showing that his children are far better educated than Harper's. Ben arrives at Leslie's funeral with their children against Jack's wishes and reads her will, which instructs her family to cremate her and flush her ashes down a toilet, in the hopes of convincing Jack to honor her wishes, only for Jack to have him forcibly removed from the church. Angered by Jack's refusal to honor Leslie's wishes, Ben follows the funeral procession to the cemetery, planning to intervene, despite a police presence and Jack's threat to have him arrested. Ben only relents at his children's insistence that they cannot lose both of their parents. After this, some of Ben's children start to doubt him and his parenting skills, with his second eldest son and middle child Rellian accusing him of failing to treat Leslie's mental health, and eldest son Bodevan accusing him of not equipping them for the real world, showing him acceptance letters from several top
Ivy League colleges to which Leslie had helped him apply. Ben finds a note from Rellian, who has run away to live with his grandparents. When Ben visits Jack to get Rellian back, he refuses to go back with him, wanting to stay with his grandparents. Jack berates Ben and accuses him of child abuse, telling him he is filing for custody of all of Ben's children. When one of Ben's older twin daughters Vespyr tries to clandestinely exfiltrate Rellian from their grandparents on Ben's orders, she falls from the roof and narrowly avoids breaking her neck. Ben, shocked and guilty when the hospital tells him how close she was to death, allows Jack to take his children. Jack assures Ben he's making the right choice by leaving his children in their care, and Ben drives off in his bus, feeling sad without his children. However, the children dislike living in their grandparents' capitalist environment and miss their father, so have stowed away in the family bus, and reconcile with their father. The children desire to honor Leslie's final wishes, and persuade Ben to help them.
Exhuming her corpse, they burn it on a
funeral pyre by the ocean, and perform a singing ceremony in her memory. As per her wishes, they then flush her ashes down an airport toilet. Bodevan then leaves the family to travel to
Namibia, while the rest return home. The final scene shows the children eating breakfast around the kitchen table with their father and getting ready for the school bus. ==Cast==