During a 2006 Paris renovation, Claire pries open a bricked-over door and steps into an apartment sealed since 1942-lace curtains, ration cards, a child's shoe, and letters to "H." The city once outside that wall was Nazi-occupied Paris. Inside, teenage Hanna Rosen survived in whispers: a heating register as lifeline, forged names as armor, each knock a gamble. When hiding can no longer hold, Hanna embarks on a perilous journey across a war-ravaged Europe-safe houses, mountain crossings, and shadowed consulates-fleeing relentless Jewish persecution and chasing a path to freedom. In the present, Claire becomes obsessed with reconstructing that route and Hanna's ultimate fate. Archives, aliases, and a painting draw rivals-an art dealer and a "supposed descendant"-into a battle over ownership and truth. As the past tightens its grip, Claire must decide what she'll risk to let the dead speak and to give one vanished girl the ending history never wrote.