This book is about the choices people make and why they make them.
A family grows up around a huge secret. A mom gives birth to twins on a snowy night and only dad (a doctor) and a nurse who works with the doctor are there. She has a beautiful baby boy, and then proceeds to give birth to his twin, a girl with Downs syndrome, at this point the mom is knocked out and her husband makes a split second decision that he has to live with for the rest of his and everyone else's life. He tells his nurse to take the baby girl to an institute he believes that he's doing the right thing for his wife and son and saving them a lot of heartache, so he ends up telling his wife their baby girl died.
The nurse takes the baby to the institute, but can't leave her there. She ultimately decides to take the baby and raise it as her own.
This is all in the first couple of chapters, and the rest of the story is about how their lives are all affected by his decision he made that night, and how and why he doesn't tell them.