By Bret Lott

Random House. 303 pp. $24.95

Simplicity is a virtue, except in the world of novels, where the most successful fictions generally raise more questions than they answer. Bret Lott's sixth novel, "A Song I Knew by Heart," is an ambitious attempt to portray an old woman's grief as a stripped-down, bare-bones condition, a spiritual exile that forces her into a prolonged evaluation of her faith. For the author, the trick here is to present these straitened circumstances without being simplistic. Does Lott succeed?

Naomi Robinson is a widow in her seventies who has been living with her son, Mahlon, and daughter-in-law, Ruth, since the death of her husband, Eli, eight years ago. When Mahlon is killed in an auto wreck on a wintry night, Ruth, now herself a widow, echoes the Old Testament Ruth when she pledges her loyalty to her mother-in-law: "Where you go, I will go. Where you live, that's where I'll live too." Together, the two distraught women decide to move from Massachusetts, where Ruth was born and where Naomi has lived for the last 56 years, to the coastal South Carolina town of Naomi's girlhood.

Before the move, however, Naomi has to endure some painful goodbyes: first with her close girlfriends, then with Lonny Thompson, her husband's business partner from years ago, who is now dying of cancer. Lonny -- whom readers of Lott's fiction may remember as a character in his 1987 novel "The Man Who Owned Vermont" -- hasn't spoken much to Naomi over the years because of a guilty secret they have shared. When she was a young bride, despairing over her inability to conceive a child, she indulged in a reckless one-time afternoon infidelity with him. Shortly thereafter, Eli and Lonny dissolved their business partnership, while in time Naomi became pregnant with Eli's son, Mahlon.

Over the years of their otherwise long and happy marriage, Naomi and Eli never spoke about her infidelity, although that one indiscretion in her otherwise blameless life has tortured her ever since. Now, in a strained conversation at the cemetery near her husband's and son's graves, Lonny confesses to Naomi that he had told Eli about their misdeed and that Eli had forgiven them both. Naomi, who knows she ought to feel joy at this news, finds more reasons for despair: "I did not know what to do with this forgiveness, did not know where to place it or where to hide from it, or how to hold it."

Instead, she flees with Ruth to South Carolina, where relatives of Eli's are eager to take the two widows in. In the months that follow, while Ruth is able to take steps toward restarting her life, Naomi feels increasingly isolated, unable to find solace in either the dwindling familiar landmarks from her childhood or in Eli's family's gracious embrace. But Lott does not allow despair to have the last word. Hope reasserts itself in the form of Eli's step-nephew Beau, a firefighter with perfect manners, whose polite interest in Ruth helps to restore Naomi's faith in the future.

Surely no one could fault Lott for wanting to create, as he does here, a faithful contemporary adaptation of the Old Testament Book of Ruth. That sacred text is, after all, a rich and moving story that makes significant contributions -- though in very different ways -- to the religious narratives of both Jews and Christians. The problem is that Lott's version, unlike the ancient story that inspired it, suffers from a dispiriting homogeneity. Not only is every character in his novel a devout Christian, sharing the same set of beliefs, but each person also exhibits the same bland demeanor. Every character, not just firefighter Beau, is unfailingly courteous, unfailingly solicitous of other people's feelings. In scene after scene, tears are choked back, voices are hushed, graciousness and prayerful earnestness are universal. Even the pillow talk here feels chaperoned: Naomi's most intimate conjugal moments with Eli, recounted among her happiest memories, consist of a mutual whispering of "Nice to meet you."

With its numbing politeness, unrelieved by humor or hubbub, "A Song I Knew by Heart" blends its emotional ingredients -- grief, compassion, guilt, regret -- into a mixture as opaque and quivery as banana pudding. Lott has proved himself capable of much more dynamic writing in the past: His 1991 novel "Jewel," which became one of Oprah Winfrey's book club selections, was every bit as earnestly sentimental as this new book but far more enjoyable to read. That's in part because "Jewel" managed to highlight the complexity of the differences in human expression, instead of imposing an oversimplifying sameness that makes Lott's new book an insipid experience.