Abigail Gibson is gone. The morning after Christmas Day, she walks out of her home in the leafy suburbs of Westchester, New York, leaving behind a strange note on the kitchen table... and her ten-year-old son, Sam. When her sister Gillian gets the call, she can barely believe it. Abigail has always been a little, well, unreliable, but she hasn't done anything like this in a decade--not since Sam was born. Now...