Where the Heart Is

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At seventeen years old and seven months pregnant, Novalee Nation (Natalie Portman) sets off on a road trip from Tennessee to California with her boyfriend, Willy Jack Pickens (Dylan Bruno).
While driving through Sequoyah, Oklahoma, Novalee notices her shoes have fallen through the hole on the floor of the car while she was napping. She asks Willy Jack to stop at the local Walmart so that she can go to the bathroom and buy new shoes. When Novalee reaches out for her change at the checkout, the sum of $5.55 sends her into a panic as we learned early on that she believes that the number 5 is a bad omen. She runs barefoot outside to discover that Willy Jack has abandoned her and left only her new camera behind.
Having no where else to go, she walks back inside and meets Thelma "Sister" Husband (Stockard Channing), a woman who runs the Welcome Wagon in town and gives her a Buck Eye Tree. Novalee also meets a photographer named Moses Whitecotton (Keith David) who advises her to give her baby a strong name. Later that evening, Novalee feels sick and runs into the bathroom again to vomit. When she comes out again, she discovers that the store is closed. She soon figures out how to live undetected in the Walmart.
Meanwhile, Willy Jack is arrested and accused of fraternizing with an attractive stranger he had no idea is actually 14 years old. He is sentenced to serve time where he composes a country song entitled "Beat of the Heart."
Novalee manages to live at the store for several weeks. She visits the library and meets Forney Hull (James Frain) who looks after his librarian alcoholic sister Mary Elizabeth (Margaret Hoard). After finding the info on how to tend to a Buck Eye Tree, Novalee visits Sister Husband where she agrees to let Novalee grow the Buck Eye tree in her yard.
Novalee wakes up during a thunderstorm as she starts having contractions. Her water breaks, and she goes into labor. As she collapses, she notices that she is in Aisle 5 and manages to pull herself to the next aisle as she continues her screams. Forney (who saw her go into the store at closing time) jumps through a plate-glass window and helps deliver her baby offscreen.
The next morning, Novalee wakes up in the hospital to find she is a media celebrity for giving birth in a Walmart. She befriends her nurse Lexie Coop (Ashley Judd) and tells her that her daughter's name will be Americus. Lexie reveals that she is a single woman with four children by three different men. While Novalee and Lexi are reading letters, Novalee's mother Mama Lil (Sally Field), who abandoned her as a child, has seen her on television and appears at the hospital. Her mother says the two women can get an apartment together, takes the $500 that Novalee received as a gift from the President of Walmart, and agrees to pick up Novalee and Americus the next morning. Her mother never shows up and Sister Husband comes to pick up Novalee and offers to let Novalee and the baby live at her house.
Novalee enjoys her life at Sister Husband's where she fits back into her old clothes, becomes friends with Forney, and works at Walmart. One night while Novalee and Forney are getting Christmas trees, Forney remarks that Americus is 5 months old that day. Novalee is alarmed at the realization and hurries home to check Americus. She comes home to find police at her home and learns Americus has been kidnapped. Novalee remembers that in the hospital, she received a card from Mississippi saying her baby was an "abomination under God" because she was born out of wedlock. The police quickly apprehend a vehicle with Mississippi plates and Americus is found safe in a nativity scene outside a church.
Upon being released from prison and making it to Las Vegas, Willy Jack becomes a one-hit-wonder with his song and teams with music agent Ruth Meyers (Joan Cusack) who gives him the "Billy Shadow" name.
Three years later, Novalee begins a career as a photographer with the help of Moses. When a tornado blows through Sequoyah, Sister Husband is killed offscreen, and their home is destroyed. In memory of Sister, Novalee shoots a picture of Americus and the still-standing Buck Eye Tree amidst the damage from the storm. After the funeral, one of Sister Husband's friends from AA informs Novalee that she is the beneficiary of Sister's estate. Novalee builds a new home for herself and Americus on Sister's land.
In Las Vegas, Willy Jack attempts to branch out his career and starts speaking with a well-known agent named Johnny DeSoto (Richard Nance). At the same time, Novalee who is also in Las Vegas, enters her photo in a contest and wins. Ruth Meyers informs Willy Jack in his hotel room that his old cellmate Tommy Reynolds is suing him for the credit of the song he's recorded. Willy Jack stated that he wrote the song and asks Ruth what to do. Ruth tells Willy Jack that he should ask Johnny DeSoto to help him (having somehow found out about his talk with him) and terminates her connections with Willy Jack.
Novalee returns to Sequoyah after the event. One day, Novalee receives a call from Lexie's oldest child. She rushes over to find Lexie bruised and battered. We learn that Lexie's new love interest has molested her eldest children and nearly beat her to death as she attempted to protect them.
Mary Elizabeth later passes away and when Forney does not appear at the funeral, Novalee finds him in a hotel and comforts him. They act on their feelings and spend the night together. Forney confesses his feelings for her. Novalee confides in Lexie what has happened between herself and Forney and learns that Lexie is seeing someone new. Lexie is embarrassed to admit he is an exterminator and does not have quite the physical attributes she's gone for in the past. Lexie eventually falls in love with the exterminator Ernie (Bob Coonrod) after learning he gave his ex-wife his restored 1967 Chevy Camaro in exchange for custody of his step-daughter whom he adopted as his own. They get married, and Lexie tells Novalee that she's pregnant. Novalee feels deeply that she is not good enough for Forney and struggles through telling him she does not love him. He returns to school in Maine.
Severely depressed at his ruined career following the lawsuit, Willy Jack becomes an alcoholic and starts popping pills while driving with a woman. He wanders off drunk and collapses on a railroad track where he is unable to move as a train approaches.
On Americus's 5th birthday, Novalee picks up a newspaper and sees an article about Willy Jack having lost his legs some months before and recently having been robbed of his wheelchair. Novalee visits Willy Jack in the hospital and he reveals to her that he lied to her on their last day together when he said he couldn't feel the baby's heart. He confesses his whole life would've been different if he'd been able to undo this one lie.
Novalee realizes that she has made the same mistake with Forney. She drives Willy Jack home to Tennessee and then continues to Maine to find Forney. Novalee tells him she really does love him and they return to Oklahoma and marry. The final scene is of their wedding, which takes place in a Walmart.

Question: What destroyed Sister Husband's home?
Answer: A tornado