British operative Felicity "Flick" Clariet, her confidence shaken by a previous disaster, is given the nearly impossible task of recruiting and training a group of six women, to be known as the Jackdaws, to infiltrate and destroy Europe's largest telephone exchange, sabotaging German communications in preparation for D-Day.

In January 1958, the midst of the Cold War, Luke Lucas wakes alone on the ground in a railway station with no idea how he got there--and finds that he must recover lost memories that others are glad he has forgotten if he is to save the launch of Explorer I, America's attempt to top the Soviet Union's Sputnik.