Sam Peek's children are worried. Since that "saddest day" when Cora, his beloved wife of fifty-seven good years, died, no one knows how he will survive. How can this elderly man live alone on his farm? How can he keep driving his dilapidated truck down to the fields to care for his few rows of pecan trees? And when Sam begins telling his children about a dog as white as the pure driven snow -- that seems invisible to everyone but him -- his children think that grief and old age have finally taken their toll.