In Jodi Picoult’s 19th novel, “Lone Wolf,” Luke Warren describes what it was like to leave his family in New Hampshire and join a wolf pack in Canada. As a scientist, he had spent years in close-up study of captive wolves, but once in the wild, he felt terrified and tested. Gradually, though, Luke was accepted by the animals he revered. His wolf brethren provided him with meat from their kills. When he was injured, they licked his wound open and saved him from infection.

Almost a year later, when Luke stumbled out of the forest and back into his old life, he was a stranger to his wife, Georgie, and their children, Edward and Cara. The whole human world felt alien. At a doctor’s office, he marveled that the receptionist allowed strangers to approach without first signaling their submission. In the waiting room, he smelled another patient’s sickness in her blood.

Only his reunion with the captive wolves he knew so well brought joy. To celebrate, he devoured half a calf with them. “I wedged myself in between Kladen and Sikwla,” Luke recounts, “baring my teeth and curling my tongue to protect the food that was rightfully mine. I lowered my face to the carcass and began to rip off strips of raw flesh, bloodying my face and my hair and snapping at Sikwla when he came too close.”

As Luke’s wolf family thrived, his human family began to fall apart.

Picoult tells the Warrens’ story in her trademark style, alternating the characters’ points of view chapter by chapter. When it comes to Luke, there’s a twist: As the book opens, he lies unconscious in a hospital bed, brain-damaged after a car wreck. We hear of his past through excerpts from his published memoir about the wolf-pack days in Canada.

”Lone Wolf: A Novel” by Jodi Picoult (Emily Bestler Books/Atria)

Should Luke be kept alive by artificial means? What outcome would he have wanted? Luke’s children disagree fiercely about the answers to these wrenching questions, a deadlock that is at the novel’s center.

Using just the right amount of medical lingo, Picoult effectively weaves together the neuroscience of traumatic brain injury with the ethics of potential organ donation. As we read, we can’t help but imagine a loved one in Luke’s awful situation: “He does have cognition,” a doctor explains. But “the other injuries to his brain stem prevent him from being able to access it.” Luke’s aware brain is severed from any knowledge of his own thinking.

The way Picoult portrays Luke is jarringly intense. In his family’s memories, he lived at extremes that emitted a supernova glow. His excesses seem to bleed into the other characters. Edward storms into his father’s hospital room and makes a move beyond plausibility. Cara bursts out with statements in court that strain credulity to an equal degree.

Even the minor characters are over the top. Edward describes a judge with “frighteningly yellow hair” who wears a judicial robe with “a profusion of lace at the collar that makes me think of a rabid, frothing dog.” A court-appointed guardian is called Helen Bedd, a sexy joke that Picoult rams home.

And the wolves! Their lives are often used to mirror events unfolding in the Warren family. Oddly, though, Picoult gifts them with nearly supernatural abilities (a shame because real-life wolves are fascinating enough). Luke reports that even before she is pregnant, an alpha female knows the number of pups she will birth, their sex, and whether they will stay with her or go live elsewhere. While stalking a moose, the alpha stations two of her hunters at the prey’s shoulders to assess its heart rate, a strategy that helps her decide when the kill should take place.

And Luke isn’t consistent in displaying his wolf knowledge. Early on, he notes that “there’s not a single documented case of a healthy, wild wolf killing a human.” Later, in considering what Native Americans know about the wolf, he paints a different picture, ominous and undeserved: “If we don’t keep our children close by, if we don’t value the knowledge our senior population has accrued, if we leave our garbage around, the wolf will overstep its bounds to let us know we’ve made a mistake.”

The mix of family emotion, medicine and courtroom drama in “Lone Wolf” will be familiar to fans of Picoult’s “Plain Truth” and “My Sister’s Keeper.” Compulsively readable, these earlier books infused anything-but-routine family drama with genuine plausibility. That right balance is missing in “Lone Wolf.” What’s left is a pack of characters roaming out of control. Even as I turned the pages to discover Luke’s fate, a howl of disbelief lodged in my throat.

Lone Wolf

By Jodi Picoult

Atria. 421 pp. $28