The book follows narrator Sarah Parsons, who discovers she has altered the course of history through the use of a psychic ability that has been passed down through the women living at the family's ancestral estate outside of Annapolis, Maryland.

Unbeknownst to Sarah, her actions at the end of Amber House propelled her and her loved ones into an alternate reality: North America is a collection of separate nations—including the American Confederation of States, which still struggles with segregation and sexism—and Nazis control all of Europe.

With little recollection of what happened in Amber House, Sarah must rediscover her psychometric ability (which was suppressed in this timeline by her grandmother Ida and mother Anne after use of the "family gift" nearly killed Maggie) and track down "echoes" of the past that will help her remember the way things used to be.

Sarah is once again thrown together with Richard Hathaway, whose senator father is about to run for the Presidency, but finds she inexplicably yearns for Jackson Harris, little knowing how close the two grew in the time before.

With the help of Jackson's precognition, Sarah realizes that a mysterious artifact that belonged to the Captain and that was passed down through the generations to Richard's mother Claire Hathaway may prove vital to pinpointing how time went wrong.