A family assembles at its country house for a memorial to a lost son. In the course of the long weekend, old and new tensions — between husbands and wives, between parents and children and among siblings — bubble to the surface.

It could be the plot of a Chekhov play or a Woody Allen movie. But on this classic narrative scaffolding, Joshua Henkin develops a painfully contemporary situation. The youngest child and only son of the Frankel family, Leo, was killed in Iraq on the Fourth of July, 2004 (on fictional assignment for Newsday, sad to say). On the first anniversary of his death, the family is gathering for the unveiling of his tombstone.

At the service, his sister Lily, a D.C. lawyer, remembers a stray dog her brother adopted when he was 12. “There was only one way you could get Kingman to pay attention to you,” she says. “If, for example, Clarissa and I were walking her and Clarissa had to leave, Kingman would strain after Clarissa. But then if I was the one who had to leave, Kingman would strain after me. She didn’t want us to separate. Leo called her the Togetherness Dog. And he was like that, too. He was the Togetherness Person.”

The Frankels have definitely lost their Togetherness Person. After a year of rage expressed in editorials against the war, 69-year-old mother Marilyn is spent and adrift; she plans to leave her husband, David, and announces it to the kids at their first dinner together.

This dinner has already been ruined by the behavior of daughter Noelle, now an Orthodox Jew living in Israel. Arriving at the gathering with her obnoxious husband and four young sons in tow, she rejects the kosher meal her parents have specially prepared and passes out bagels brought from home to her family. If sister Lily hadn’t already broken her vow not to fight with Noelle, this would certainly be the end of it.

Meanwhile, their older sister, Clarissa, is too obsessed by her infertility problems to be fully present, arriving hours late because sudden ovulation required her and her husband to visit a roadside motel. Meanwhile, Leo’s widow, who has come from California with his young son, Calder, is moving on to a new relationship and feels more out of place than ever with this family of feisty, competitive tennis and crossword mavens.

The skill with which Henkin explores the points of view and personae of his ensemble cast is masterful. From the aging, defeated patriarch to the innocent 3-year-old (“More than once, he’s been asked by some unknowing soul where his father is, to which he has responded, cheerfully, “He’s dead!”), Henkin depicts each in terms of their response to loss, both its damage and its unfolding trajectory. This was a central issue in the author’s well-received “Matrimony” as well. Both novels explores with subtlety and feeling the meaning of family — those we are born with and those we choose, those we leave behind and those with whom we soldier on.