Two women fleeing their marriages collide on a fog-shrouded Connecticut road. A nine-year-old boy, his father, and the woman who killed their mother and wife are left behind to deal with the repercussions of a tragedy that spread outward like ripples on a pond. That premise teems with possibilities that Caroline Leavitt explores with deftness and consummate sensitivity in this, her ninth novel.

Fellow residents of a small Cape Cod town, and now in their mid-30s, Isabelle Stein and April Nash both married impulsively and young. When Isabelle discovers her husband’s five-year-long affair and his girlfriend’s pregnancy, she flees, flinging her wedding ring out the car window as she drives. April’s departure without any cause, seemingly more substantial than a routine marital tiff that morning, is more mysterious. Hidden in the back seat of the car is her nine-year-old son Sam, a fragile, asthmatic boy who has fallen asleep under a blanket after wandering off from school. Panicked when Sam’s asthma flares and three hours from home on an unfamiliar road, April stops, and is struck and killed by Isabelle’s car.

Though Isabelle’s injuries are minor and it’s soon clear she bears no responsibility for the accident, her emotional recovery is an ordeal, made worse when she discovers that April’s husband and son live only six blocks away. “They could have passed each other on the street all the time,” she reflects. “They could have been friends.” She haunts the Nashes’ neighborhood, observing their grief from afar, desperate for a glimpse into their lives.

Baffled by the distance April traveled and the suitcase in her car, Charlie tortures himself over his petty irritation on the day of the accident: “He thought about the day April left, the morning when all he had to do was say different words and she might have stayed.” His attempt to comprehend the inexplicable circumstances of her death is the tantalizing mystery at the novel’s core. And Sam, lovingly told by his grandmother that his mother has become an angel, recalls a fleeting glimpse of an angelic-looking Isabelle at the accident scene and imagines the woman will reunite him with his mother.

It’s giving nothing away to reveal that the lives of Isabelle, Charlie and Sam slowly intertwine as they struggle to reclaim the lives the accident has stripped from them. Isabelle, squandering her talents at a studio that specializes in children’s portraits, introduces Sam to photography. He quickly develops an aptitude for the art, but focuses his attention on black-and-white photographs of “cars moving away, of empty, winding roads.” Charlie and Isabelle’s mutual attraction grows, but the way the triangle they form with Sam takes shape is anything but predictable. Despite a few patches of overwrought dialogue and a melodramatic plot twist or two, Leavitt’s mastery of both character and story is consistently apparent.

PICTURES OF YOU succeeds largely because of Leavitt’s ability to inhabit the being of Sam Nash. Unlike the jarringly precocious Miller Le Ray, protagonist of Brock Clarke’s recent novel EXLEY, there’s utter realism in her portrayal of the child: his frailty and isolation, his longing for his mother and his belief in Isabelle’s angelic powers. From acting out with the class bad boy to his struggles with asthma (portrayed with graphic realism), Leavitt perfectly channels both Sam’s sorrow and how ill-equipped he, like any child, is to shape a response to it.

Leavitt also explores the adult survivors’ grief with subtlety, understanding that they can move on without truly recovering, not least because at some level they choose not to. “You never got over what you lost,” Charlie Nash thinks. “You always carried it with you, stitched to you like Peter Pan’s shadow. And you never wanted to get over it, because who wanted to forget a time that had been so important? No, the truth was, you wanted to remember it always.” Isabelle’s friends urge her to move on, “as if she were a stalled car that only needed a little push.”

There are many strands to this mature story, and Leavitt knits them together with loving attention and care: the emotional forces that attract us to each other and then inexplicably fray; the role of sheer chance in our existence; the ways in which lives are reclaimed, though damaged, after a devastating loss. A lesser writer might yield to the temptation to offer a collection of soothing answers to these profound mysteries. It’s a tribute to Leavitt’s skill that she has written a novel that doesn’t hesitate to look into the darkness and somehow find salvation and grace there.