David Mitchell's novel "The Bone Clocks," one he has described as the latest installment in an "übernovel," is a frequently entertaining, if flawed, work. While most of it will appeal to admirers of character- or plot-driven novels, it's likely only fans of movies such as "The Matrix" or "Inception" will be enchanted by the supernatural plot thread that feels as though it would be a better fit in a Dan Brown thriller.

The novel consists of what Mitchell has called six linked novellas, their connective tissue supplied in the person of Holly Sykes, who begins the story in 1984 as a 15-year-old runaway from her London home and ends it nearly six decades later on Ireland's West Coast, in a collapsing post-technological world. In between, Mitchell juggles an impressive array of settings and well-drawn characters, a task he executes with aplomb.

But the book founders in its fifth, and longest, section, where a battle is waged between two groups of time travelers: the Horologists, who die and are resurrected in new bodies 49 days later, and the vampiric Anchorites, who "decant" the souls of children to achieve eternal life.

If you're fond of this sort of feverish dialogue — "The generator prevents a psychosoteric from using an Act of Suasion to make me deactivate the N9D" — or can distinguish characters named Unalaq and Sadaqat, then you probably will enjoy the bewildering account of the antagonists' apocalyptic clash. But those who have been enchanted by the effortless rhythms of Mitchell's prose and his storytelling skill may find themselves skimming paragraphs that don't seem to make much sense on first reading and might not on second, fourth or 10th.

"A book can't be a half-fantasy any more than a woman can be half-pregnant," says an exasperated literary agent in the wickedly funny story of a failing midlist novelist's wanderings in the literary world that's one of most entertaining set pieces in "The Bone Clocks." What makes the science-fiction plot turn so frustrating is Mitchell's sure hand in all the other aspects of this book. Whether it's the shock of a terrorist bombing in Baghdad in the story of Holly's partner, Ed Brubeck, a correspondent in 2004 Iraq, or his portrait of the lovely and lawless Irish coast in a concluding section that's simultaneously chilling and moving, in his best moments Mitchell is an enthralling writer.

There's no shortage of ambition in this novel, and the strongest parts of this book are so good they almost allow us to forgive Mitchell his lapses — ones that would be fatal in the hands of a lesser writer — while we look forward eagerly to his next work.

Harvey Freedenberg is a freelance reviewer and member of the National Book Critics Circle. He lives in Harrisburg, Pa.