As the title of Diane Johnson's latest novel suggests, Lorna Mott — an art lecturer living in France with her second husband, Armand-Loup — returns to her hometown of San Francisco, having tired of Armand-Loup's infidelity. Lorna's "principal resolve" is to help her three grown children, each of whom suffers financial troubles (as does Lorna herself).

Lorna's first husband, Ran, is enormously wealthy, the result of his marriage to a tech investor. In "Lorna Mott Comes Home," Johnson uses this wealth to fuel all manner of conflicts, both tacit and public, among the Mott family. The results are often quite funny and frequently unfair.

As Lorna imagines that she will help her children, her children plot to help their mother. (In a particularly amusing chapter, Peggy, the eldest, uses pseudonyms to post positive reviews of her mother's book.)

Lorna's sons are less clearly drawn, particularly Curt, who abandons his family and moves to Thailand when he wakes from a coma. Johnson does a superb job of establishing the small, privileged universe of Ran's second family — his wife, Amy, their daughter Gilda — and the way money inoculates them from some harm without making them invincible.

Many chapters open with a kind of platitude or declaration — "There is no gossip like family gossip," Johnson writes, and "Life more often than not defies our wishes" — after which the tone re-establishes its spectacular wit and humor. The novel's interest in gossip and unpredictability invites an astonishing series of coincidences and connections, so that Lorna's real estate agent turns out to have at least two strong ties to the Mott family; likewise, the reverend who Lorna runs into in a convenience store, an old college friend, later declares his love for her.

By the closing pages, numerous Californians are in France, renting the house Lorna once shared with Armand-Loup. These entanglements are unhampered by probability; rather, the novel examines a kind of accidental community-building through relationships.

Johnson has great ease with wry asides, from jokes about Bay Area traffic to the slightly disapproving declaration that "Californians" are "optimistic most of the time." In France, Lorna's neighbors appraise American expatriates: "The junior-year-abroad types were the worst." There are endless strings of smart observations, tucked next to moments of real vulnerability and fear.

Lorna maintains an inaccessible quality even as she asserts herself back into her family's life, and this inaccessibility may be part of the point; by the novel's close, Lorna's definitions of home and family shift considerably as she reaches a better understanding of herself.

Jackie Thomas-Kennedy's writing has appeared in Electric Literature, Lenny Letter, Narrative, Harvard Review, and elsewhere. She held a Stegner Fellowship at Stanford University.

Lorna Mott Comes Home

By: Diane Johnson.

Publisher: Alfred A. Knopf, 322 pages, $27.95.