When a modern woman inherits a Parisian apartment undisturbed since WWII, she discovers that it may hold the key to unraveling her cold great-grandmother's secret life -- a past of sacrifice during a mission to protect those she loved.

1940, Paris
As the heiress to a wealthy Parisian family, Lise Allard grows up immensely privileged, but barely knowing her absentee parents. Instead, she finds her own sense of family among a close circle of friends. Yet when war breaks out and Paris is occupied, she sees her friends taken away one by one. Heartbroken, Lise vows that she will do whatever it takes to help defeat the Germans.

2017, Paris
When Aurelia Leclaire's great-grandmother passes away, the last thing Aurelia expects to inherit is a tiny Paris apartment untouched for over half of a century. But even more shocking is the massive collection of priceless jewelry and fine art secreted inside. When she discovers an unknown painting cherished by Lise, she realizes that it may be the key to unlocking her great-grandmother's story.

Art appraiser Gabriel Seymour is contacted by a woman who claims to have found a painting by his great-great-grandfather. While unearthing its story, Gabriel and Aurelia discover a hidden cache of weapons, encrypted letters, and faded passport photos revealing intertwining family connections and betrayals from the past.