In Ariel Lawhon's "The Frozen River," narrator Martha Ballard reveals how a person would navigate the river that flows through Hallowell, Maine, in the late 18th century: "There are only two ways to cross the Kennebec: by ferry in warmer months, or by foot once it's frozen."

When Martha, the town's midwife and healer, is summoned to examine a body pulled from the water one bitterly cold morning in November 1789, she finds a bruised and battered man who clearly didn't die from falling through the ice. Martha determines a different cause of death: The victim was beaten and hanged, then thrown in the river. She also confirms his identity — Joshua Burgess, one of two men accused of raping the pastor's wife, who is Martha's friend, Rebecca Foster.

The second accused man is the town's judge, Colonel Joseph North, who fiercely denies the allegations leveled against him. Martha believes otherwise, having listened to Rebecca's heartrending account of her ordeal and tended her physical injuries — at the same time aware that "[t]here is no mending the kind of damage they had done." Martha is also convinced the two crimes are connected and hopes North will be suitably punished when he stands trial.

In the meantime, North proves a ruthless adversary, one determined to discredit Martha's version of events and thwart her progress at every turn. Martha also finds herself up against Benjamin Page, a Harvard-educated doctor who belittles her medical knowledge and declares Burgess' death an accidental drowning. But then tongues start wagging and both Rebecca's husband and Martha's son are suspected of murder. As North starts to make life difficult for her family, Martha decides to go it alone and do whatever it takes to find justice.

To date, Lawhon's novels have cleaved closely to historical fact. "The Frozen River" marks a departure of sorts from her usual practice: It is, according to the author, inspired by real events rather than based on them. Lawhon may have taken artistic liberties but her gripping tale still feels like an authentic foray into the past and her wonderful heroine rings true.

Indeed, Martha is so vividly rendered that it is hard not to become absorbed in her narrative and emotionally invested in her life. We follow her over the course of a winter — "such a cruel season" — as she carries out her investigation in a community torn apart by scandal, while also witnessing her children's budding romances and helping women in need, particularly those who have conceived children out of wedlock.

The book contains a range of compelling scenes, from fraught births to electrifying court cases to tense confrontations. Scattered Shakespeare references enrich the proceedings. Martha's journal entries flesh out further this tough, brave and resourceful woman. Her valiant fight against the evil that men do makes for a winning blend of fact and fiction.

Malcolm Forbes has written for the Times Literary Supplement, the Economist and the Wall Street Journal. He lives in Edinburgh, Scotland.

The Frozen River

By: Ariel Lawhon.

Publisher: Doubleday, 432 pages, $28.