In the beginning, the kids are alright. The adults, though, are already sliding toward Sodom and Gomorrah.

That’s the starting point of Lydia Millet’s novel “A Children’s Bible,” which offers a bracing reflection on the generational conflict playing out in the atmosphere. I swear on a stack of copies that it’s a blistering little classic: “Lord of the Flies” for a generation of young people left to fend for themselves on their parents’ rapidly warming planet.

Millet writes brilliantly about everything — politics, physics, mermaids — and she’s one of the leading writers of environmental fiction. As Richard Powers did in his Pulitzer Prize-winning novel, “The Overstory,” Millet addresses the existential crisis of climate change with a technical understanding of the science and a humane understanding of the heart. She’s also ferociously witty. That rare combination has made her stories about species extinction and global warming profound and weirdly amusing. (She’s a tough critic, too. A few years ago, she eviscerated me in The Post’s letters column.)

“A Children’s Bible” moves like a tornado tearing along an unpredictable path through our complacency. It begins as a snarky teen comedy. A group of families has rented an old mansion together for the summer. The adults are all embarrassing, drunken bores. “As the evenings wore on, some parents got it into their heads to dance,” Millet writes. “A flash of life would move their lumpen bodies. Sad spectacle . . . . They were a cautionary tale.”

The narrator is a teenager named Evie, one of several sardonic older kids in a large group of young people with free run of the house and grounds. The dialogue is a pitch-perfect re-creation of those transitional years when adolescents are still trailing clouds of childhood while beginning to grasp the challenges of adulthood. Deprived of their cellphones and Internet access — “We were being held in an analog prison” — the kids cavort in the woods, paddle off in rowboats, make out in the attic. Their primary group entertainment is trying to deduce which insufferable parent belongs to which member of their gang. “Sometimes a parent would edge near,” Evie says, “threatening to expose us. Risking the revelation of a family bond. Then we ran like rabbits.”

Evie is a captivating narrator, switching effortlessly from the bored disgust of an impatient teen to the thoughtful insight of a mature young woman. She speaks in the first-person plural — “we” — for such sustained passages that sometimes the novel sounds like the communal voice of adolescence. But in an instant, Evie can feel removed and separate, wholly devoted to protecting her little brother, Jack — which is important because their parents aren’t paying attention at all.

These pages repel sentimentality on a cellular level, but how delicately Millet portrays little Jack. Like one of the woodland animals of which he’s so enamored, the boy is mesmerizingly fragile and vital, with a mind balanced between naivete and wisdom. One day, while the other kids are playing, an adult hands him a children’s Bible to keep him entertained. “It’s a bunch of stories with pictures,” he explains to Evie. “There are people and animals, but not as nice as George and Martha.” Jack comes to the Scriptures with no religious training. (He once asked his parents about the long plus sign atop a Baptist church.) Equipped only with his deep curiosity and knowledge of the natural world, he studies the Old and New Testaments with the care of an anthropologist and the curiosity of a biologist. His new hobby seems harmless, but God and Millet work in mysterious ways.

Behold: “A Children’s Bible” is ready to rain down God’s wrath on these hapless families. When a tremendous hurricane moves up the coast, their Gilded Age mansion is smashed by falling trees and then surrounded by polluted floodwaters. The adults panic. Confronted with gaping holes in the roof, a rising tide in the basement and no electricity, they get high, have sex, break down in fits of crying and fantasize about incremental steps they can take to fix everything. (To their credit, none of them thinks it’s a Chinese hoax.)

The storm is just the first of several calamities that will darken this comic novel as it shifts into dystopic tones. “Our vacation paradise had turned into hell,” Evie says. Suddenly, the familiar conceit of teens irritated at their inept parents takes on deadly connotations. “Once we had let them do everything for us — assumed they would. Then came the day we didn’t want them to.”

Millet begins spinning the story of Noah’s Ark through a modern-day tale of climate change to produce a shattering vision of our apocalyptic future. The novel works so effectively because it’s an allegory that constantly resists the predictable messaging of allegory. The plot is filled with sacred allusions — the Flood, angels, Bethlehem, a crucifixion, a deus ex machina and more — but they’re all skewed. Poring over the soggy pages of his children’s Bible, Little Jack isn’t converted to the environmental fatalism of evangelical Christianity; instead, he’s inspired to radical action. “God’s a code word,” he explains to his sister. “They say God but they mean nature. . . . And we believe in nature.” He’s got the whole Trinity figured out: “There’s lots the same with Jesus and science,” he says. “For science to save us we have to believe in it. And same with Jesus.” Out of the mouths of babes! But as with the prophets of old, almost nobody listens to Jack.

Millet’s wit and her penchant for strange twists produce the kind of climate fiction we need: a novel that moves beyond the realm of reporting and editorial, a story that explores how alarming and baffling it feels to endure the destruction of one’s world.

Take this book, eat it up.

Ron Charles writes about books for The Washington Post and hosts

A Children's Bible

By Lydia Millet

W.W. Norton. 224 pp. $25.95