"It was the broken-resolution end of January already ... " is how Cate Kennedy's debut novel, "The World Beneath," begins. Her characters are defined by good intentions, noble plans that often collapse in the face of day-to-day life.

Sandy is an Australian single mother, whose life arguably peaked years ago when she joined the Franklin River blockade to help save the area from development. At the blockade, she met Rich, an aspiring photographer always looking for "the defining moment."

The novel suggests that the unambiguous success of the Franklin River environmental campaign in some ways spoiled Sandy and Rich for life. Rich, still chasing the high of the protest days, abandoned Sandy shortly after their daughter, Sophie, was born.

The novel opens 15 years after Rich's defection. Sandy is feeling the distance from Sophie, who is uncommunicative with everyone except the readers of her blog, "My Crap Life." Then Rich reappears on the scene, wanting to take Sophie on a wilderness hike through Tasmania.

The novel is painfully pointed in its satire of well-meaning progressives whose grand plans to change the world have devolved into passive-aggressive jabs at each other.

Seeing each other for the first time in years, Rich and Sandy immediately engage in environmental one-upmanship. Rich is quick to point out that he doesn't own a car: "It just seems like too much of a carbon footprint, you know?" When Sandy responds with a lecture about "voluntary simplicity" and points out that she's owned her car for 14 years, Rich starts talking about "catalytic converters and old engines spewing lead into the air." He adds: "Not that I'm judging you."

These unflinching comic moments are the book's greatest strength. The characters are believably flawed, and their self-justifications for acting in selfish or insincere ways are frustratingly true to life. The dialogue-heavy mixture of contemporary comedy and social commentary is like Nick Hornby at his "About A Boy" or "High Fidelity" best: well-observed and thoughtfully funny.

Despite the comedy, a chill creeps into the latter part of the book. Anxious to prove himself, Rich takes a dangerous risk. It is here -- where, plot-wise, we are at the most exciting point -- that the book curiously loses some tension. Believability feels sacrificed in the interest of wrapping up thematic loose ends. Would Sophie and Rich really have a debate about the ethics of nature photography while scared and lost in the wilderness, for instance? However, the too-tidy ending doesn't cancel out the pleasure of the book as a whole.

Life, Kennedy suggests, is largely resistant to our schemes and resolutions. Faced with the realities of both the natural world and our thorny personal relationships, we need more than good intentions.

Laura C.J. Owen is a freelance writer living in Tucson, Ariz. You can read more of her writing at www.lauracjowen.com.