Billie Letts returns to Wal-Mart in the opening scenes of her fourth novel, “Made in the U.S.A.” (Grand Central Publishing, $24.99), which features a shoplifting gymnastics star and her younger brother.

Letts’ first novel, “Where the Heart Is,” became an American classic with its tale of an unwed, pregnant teen who eventually gives birth in a Wal-Mart store.

In her latest novel, 15-year-old Lutie McFee eases the pain of being kicked off the high school gymnastics’ team by stealing sexy clothing from the discount retailer. She’s mid-theft when her father’s ex-girlfriend drops dead at the checkout counter, leaving her and her 11-year-old brother on their own.

Fearful of foster care, the two children steal the dead woman’s car and flee to Las Vegas in search of the father who abandoned them.

The initial resemblance between “Made in the U.S.A.” and “Where the Heart Is” is striking. Both start in Wal-Mart and star teenage girls on the run with a young child to look after.

But “Made in the U.S.A” is a much darker book with an unflinching look at the hardships and dangers runaway children face. Lutie McFee is also a much tougher character than the trusting and hopeful Novalee Nation, who seemed to bring out the best in those around her.

Damaged by her mother’s early death and father’s alcoholism, Lutie is willful, spiteful and selfish. She’s redeemed by her affection for her younger brother, Fate, a budding intellectual who dreams of going to the aptly named Paradise Elementary School.

That makes the first two sections of “Made in the U.S.A.” a tough read as the two children are beset by tragedy and repeatedly victimized. But when it seems like a happy ending is impossible, Letts has a guardian angel move the children to Oklahoma, where they – like Novalee Nation – find love, acceptance and a home.

The result is a gripping 200 pages followed by an ending that feels forced. The abrupt change of scenery and lighter tone of the book’s third section makes it feel more like an epilogue than a conclusion to the original story.

Letts’ novels following “Where the Heart Is” have fallen a bit short in terms of pure reading pleasure, and “Made in the U.S.A.” is no different.

But it’s her best work since her stunning debut novel, and she still writes about America’s lower-class with a clarity few other contemporary American authors can muster.