1946, Man­hat­tan. Grace Healy is rebuild­ing her life after los­ing her hus­band dur­ing the war. One morn­ing, while pass­ing through Grand Cen­tral Ter­mi­nal on her way to work, she finds an aban­doned suit­case tucked beneath a bench. Unable to resist her own curios­i­ty, Grace opens the suit­case where she dis­cov­ers a dozen pho­tographs – each of a dif­fer­ent woman. In a moment of impulse Grace takes the pho­tographs and quick­ly leaves the sta­tion. Grace soon learns that the suit­case belonged to a woman named Eleanor Trigg, leader of a ring of female secret agents who were deployed out of Lon­don dur­ing the war. Twelve of these women were sent to Occu­pied Europe as couri­ers and radio oper­a­tors to aid the resis­tance, but they nev­er returned home – their fates a mys­tery. Set­ting out to learn the truth behind the women in the pho­tographs, Grace finds her­self drawn to a young moth­er-turned-agent named Marie, whose dar­ing mis­sion over­seas reveals a remark­able sto­ry of friend­ship, val­or, and betrayal.