Joshua Ferris' "The Unnamed" is a hero's journey tale with the heroism scoured clean off it. Its protagonist, Tim Farnsworth, suffers from an affliction in which he walks involuntarily for miles on end, and his constant motion wreaks havoc on his body and, in a way, conventional storytelling. Instead of adventure there is only movement. Instead of revelation there's only unknowing.

In short, it's grim. Tim is a partner in a New York law firm, and as the novel opens he's endured two bouts with the unnamed illness that prompts him to walk until his body gives out. The condition baffles specialists -- "benign idiopathic perambulation" is the best one doctor can do. In time, it grows malignant: He loses stable employment, fingers and toes succumb to frostbite, and his family is jeopardized as his wife, Jane, and daughter grow exhausted by his behavior.

It's Tim's story, but Jane gives "The Unnamed" what emotional depth it has. She sinks into alcoholism, and Ferris describes her despair with a terrifying matter-of-factness. Nearly all the violent moments in the novel share a chilly aspect: a bloodied foot, an attempted suicide and a car accident are described like afterthoughts. When Tim loses a toe, Ferris applies little drama to the moment: "He crumpled the toe up in a clean piece of paper and threw it away in a trash bin."

"The Unnamed" isn't always so reserved. Some scenes inside Tim's firm, for instance, recall the same black humor that powered Ferris' debut novel, "Then We Came to the End." But Tim's fellow lawyers have too much cardboard in them to make Ferris' book another workplace novel, and Tim dominates the story too much for it to be a domestic saga. Nor does Ferris focus on the details of Tim's affliction itself enough to make it a work of medical fiction. So how to classify this ambitious but unsuccessful icicle of book?

At best, "The Unnamed" has a little to say about the way men feel trapped by their need to be successful and powerful -- the state of being "in harness," as psychologist Herb Goldberg once wrote. Tim works with hypercompetitive men, serves an alpha-male client, and ponders his obligations to his wife and daughter as he roams. What novels like "Rabbit, Run" and "Revolutionary Road" did with intense realism, "The Unnamed" plays out in overworked, unsatisfying metaphor. To go Ferris' route is to walk some well-trod ground, and to come away with less.

Mark Athitakis is a reviewer based in Washington, D.C. He blogs at americanfiction.wordpress.com.