Every Last One by Anna Quindlen

Imagine that you are living your regular life. You with your own business, a successful husband, surly but high achieving teen-age daughter, twin 13 year old boys - one an outstanding athlete, the other a sullen drummer. Then imagine the most horrific thing possible happening - it doesn't matter that it be the one in this story. Now imagine that somehow you need to find a way to carry on. The sense of impending doom is clear from the beginning but I was so not prepared for what happens.