THE DARK PATH TO THE RIVER By Joanne Leedom-Ackerman Saybrook. 390 pp. $19.95

A journalist and a venture capitalist and his wife face the fallout when Wall Street stokes an unpopular African government in "The Dark Path to the River."

This gripping thriller tells the story of a journalist who puts her life in danger to learn the truth behind a revolutionary group and the dictatorship it hopes to topple. This is also the story of friendship between two women who must find enough faith in themselves to prevent the men they love from sacrificing their integrity. The novel probes the tension between money and power, business and morality, fidelity and lust.

Olivia Turner is covering the revolutionary group's appearance before the United Nations. Although economically insignificant, the country -- never named -- is strategically valuable. Ruling the country is Amundo Bulagwi, a sort of Idi Amin who dismantled a weak parliamentary government and murdered his opponents.

While members of the revolutionary National Liberation Association are in New York, a coup is attempted and pandemonium ensues. The NLA delegation hurries home to a bloody reception. The NLA's elder statesman, Robert Nyral, and its militant younger leader, Jamin Nyo, are reported killed.

When Bulagwi travels to the United Nations to deny reports of massacres, Olivia slips deeper into her story, becoming less an observer than a participant.

Meanwhile, Olivia's friend Jenny Reed undergoes a nerve-racking test of faith in her husband when they are preyed upon by Kay Walsh, a reporter who doesn't let decency get in the way of a good story.

Kay wants a scoop on the NLA. Her best possibilities are Olivia, who is trusted by Jamin and Nyral, and Jenny's husband Mark, who steered his investors' money into Afco, a high-risk company that is reopening mines in Africa. By manipulating her way into Mark and Jenny's apartment, Kay is able to peek at Afco documents suggesting double dipping and bribery and to learn that Jamin is alive. She also puts on a convincing show that she is having an affair with Mark. It's all in a day's work for her.

Author Joanne Leedom-Ackerman knows suspense like Hitchcock, and her tale has the momentum of "The Man Who Knew Too Much." But what distinguishes this novel is its characters.

Jenny, for example, never disappoints as she helps Mark find his way back to his family. When Mark tells a story about their daughter Erika to a business associate, "He sounded like so many men who knew their children's lives through the secondhand stories of their wives at the end of the day. Yet Mark knew Erika better than that. Why was he going on this way?" As Afco and Kay threaten his values, Jenny forces him to question the ends of his good intentions.

Mark seems as if he would be as happy at Common Cause as on Wall Street. But he steadfastly believes he can best help Third World countries by directing money into ventures. He tells Jenny: "Frankly, for all you or Olivia talk about the third world, you can write articles and send care packages till the birds come home, but you aren't touching the basic problem which is capital and investment."

And Olivia remains engaging throughout, largely because she never stops digging: "After two decades as a journalist she had never uncovered where the power lay. Was it in the people with money and influence? The powers of government and business often set events in motion, and yet it seemed to her that another inarticulate, insistent force took over, a reaction to the original assertion of will. Power was more like lightning, she thought, which, when conducted, created electricity, but untapped, burned down forests."

Though not enough to undermine the novel, the subplot involving Kay's son is digressive. He largely appears offstage, a thinly drawn and ultimately uninteresting brat. Also, Jenny's pregnancy is not woven fully into the piece. And one reporter, whose pursuit of a story proves fatal, is left half sketched.

Leedom-Ackerman writes in the acknowledgments that hers "is a book of discovering faith in one another and in life." This is reflected in the title, which refers to a decision by Nyral not to retaliate after Bulagwi's soldiers raid a town. Nyral's journey on the dark path to the river inspires him to have faith that evil will destroy itself. Mark, Jenny, Olivia and Jamin must find their own paths to faith, and their journeys give this fine novel its power.

The reviewer is an assistant national editor of The Washington Post.