Through her canny protagonist, Grace Winter, Charlotte Rogan begins her novel with a sentence that is sure to keep us reading. "Today I shocked the lawyers, and it surprised me, the effect I could have on them." Twenty-two year-old Grace is on trial for murder, along with two other women, for killing a man aboard the lifeboat on which they had spent 21 days.

Grace is on her honeymoon aboard the Empress Alexandra, returning to New York from London in 1914, when a fire erupts and sinks the ship.

Her husband goes down, while Grace makes it onto a boat with 38 others. The lifeboat is overloaded and rides too low on the water, a fact everyone tries to ignore until, by day eight, they realize that no one is coming to their rescue. It is then that Grace overhears their leader, John Hardie, the only crew member on board, saying softly, "Unless we lighten the load, we'll sink like a bloody stone."

We can already predict that Grace will survive, for psychological as well as structural (she's the narrator) reasons. She's an unhysterical pragmatist who sharply rebukes some of the other women for their praying and crying. We've learned much about her from flashbacks in which she coolly remembers how she stole a rich man away from his clueless fiancée by discreetly stalking him and finding ways to make him notice her.

The lifeboat becomes a microcosm of what human beings are capable of, for good and ill. Some people become sick and/or crazy and die. A few sacrifice themselves to the waves. John Hardie draws straws to determine who has to go overboard next. When food and water grow scarce, he catches fish. Dead birds fall into the boat and are devoured by civilized beings turned savages, their mouths dripping with blood. As the days wear on, selfishness, frailty and ill will gradually erode the group's initial cohesiveness. Grace thinks bitterly that she will never again believe in the innate goodness of human beings and that, having experienced the indifferent menace of the sea, she will "never again think of nature as a garden for man."

By day 14, the survivors openly speculate on who should live or be next to die. There is a coup d'état as one of the strongest, Mrs. Grant, convinces Grace and another woman, Hannah, that Hardie is no longer a fit leader and should be killed. The novel is ambiguous about this move, leaving readers to decide whether this is a rational decision or pure insanity.

Charlotte Rogan delivers a subtle and very persuasive analysis of the circumstances in which decent people can devolve into primal creatures.

Brigitte Frase is a writer and book critic in Minneapolis. She is a member of the National Book Critics Circle and the recipient of its award for distinguished book reviewing.