If there were ever any question about Larry Watson's reputation as one of the finest writers working today, there shouldn't be anymore. Not after "Let Him Go," Watson's ninth book of fiction, and his best.

Set in the autumn of 1951, "Let Him Go" is the timeless story of George and Margaret Blackledge, grandparents who set out to reclaim their grandson, who has moved from Dalton, N.D., to Montana with his mother and her suspect new husband, Donnie Weboy.

Donnie, in Margaret's mind, is a sorry replacement for her son James, whose recent and tragic death haunts her. It takes some arm-twisting, but Margaret convinces her reluctant husband to join her on the road, and before they leave Dalton behind, he makes a stop at their old ranch. Margaret, wise to his ways, says, "I've had enough loss, George." To which he replies, "You know that's what life is. Loss, fast or slow." It's a prescient sentiment, and the foreshadowing in their spoken words sets the novel in motion.

Readers familiar with Watson's stoic and laconic voice will surely recognize the timbre of "Let Him Go." The landscape is described in loving, gorgeous prose: "This is prairie, rolling gentle country where black seams of trees and brush stitch one grassy hill to another." And the subtle cleverness in both dialogue and in the emotional push and pull between characters is vintage Watson.

What distinguishes "Let Him Go" from Watson's previous novels is the relentless narrative energy. Without compromising any of his trademark style, Watson manages to tell a story that is riveting in its many twists, one that turns from sweetness to sorrow with an amazing economy.

When George and Margaret get to Montana and come face to face with Donnie and the rest of the Weboys, the pacing becomes downright explosive. The Weboys — especially the demonic matriarch, Blanche — are a villainous and territorial bunch of thugs intent on not giving up the grandson easily. What begins as a cordial request by Margaret to bring the boy back to North Dakota with his mother quickly becomes a mesmerizing and heart-stopping game of cat and mouse, one that builds expertly to a climax that is both horrific and inevitable.

Which is not to say that "Let Him Go" is simply a dark book, one that introduces evil characters merely for the sake of a driving story. There is redemption in these pages, too, and I don't think I've ever read a book that deals so convincingly with the staying power of memory, or of the power of familial love.

Peter Geye is the author of "Safe From the Sea" and "The Lighthouse Road." He lives in Minneapolis.