May 2013: Author Sarah Blake is struggling to find a big idea for her next book. Breaking a promise to her mother, she opens her great-grandfather's chest from the RMS Lusitania, sunk by a German U-Boat in 1915. What she discovers there could change history. April 1915: Caroline Telfair Hochstetter's husband, Gilbert, has become pre-occupied with business-- and something else that she can't quite put a finger on. They're traveling to London aboard the Lusitania-- and discovers her old friend Robert Langford is on the same voyage. Also on board is Tessa Fairweather, whose partner has promised that if they can pull off this one last heist aboard the Lusitania, they'll leave the game behind.