"We're climbing Mount Kenya. Not this Saturday, but the next." With that statement, the opening line of Anita Shreve's "A Change in Altitude" (Little, Brown, 320 pages, $26.99), a young doctor exacts a control over his new wife that she tries for the rest of the story to surmount.

It's an engrossing tale that combines a tense adventure yarn with travelogue, political intrigue and romance, layered with riveting detail (Shreve lived in Africa for a time).

It's the late 1970s; Americans Patrick and Margaret have moved to Kenya for Patrick's medical research. Margaret willingly, even enthusiastically, embraces this adventure, hoping to build on her budding photojournalism career. They quickly settle in, renting a house on the property of an expatriate British couple: the smug and condescending Arthur and his stylish, intimidating wife, Diana. Margaret admires and fears both of them, and when Arthur proposes to Patrick that the four of them, joined by a similarly urbane Dutch couple, climb the iconic peak, she swallows her reservations.

The climb itself, described by Shreve with heart-pounding precision, results in tragedy. Margaret not only blames herself but comes to realize that the others do, as well, including Patrick. Suddenly her young marriage is in trouble, a pall hanging over the two even as they try to paper over this trauma (and the traumas to come) with a different house, an excursion here and there, a new job for Margaret.

The job, as a freelance photographer for a radical newspaper, offers Margaret a bit of salvation and the chance to observe the harrowing existence of political activists and the Kenyan natives, women in particular.

The story, for better or worse, doesn't linger long on these broader moral quandaries; they are largely overshadowed by Margaret's personal crises, which deepen when a relationship with a handsome reporter further jaundices her view of her marriage. Indeed, the variations on "can this marriage be saved?" followed by halting rapprochements, begin to wear as thin as the rarefied mountain air.

Not until the pair embark on a second climb, more than a year after the first -- yes, it does seem a spectacularly misguided plan -- does Margaret finally gain the clarity to see that the larger-than-life Kenyan adventure has blinded her. She reaches a conclusion that's been obvious to the reader all along; but the climb, though wearying at times, has been worth it.

Cynthia Dickison is a features copy editor at the Star Tribune.