When Caroline wakes up in a Paris hospital with no memory of her past, she’s confused to learn that for years she’s lived a sad, reclusive life in a sprawling apartment on the rue Cler. Slowly regaining vague memories of a man and young child, she vows to piece her life back together - though she can’t help but feel she may be in danger.

In Nazi-occupied Paris, a young widow named Celine is trying to build a new life for her daughter, working in her father’s flower shop, and hoping to find love again. Then a ruthless German officer discovers her Jewish ancestry, and Celine is forced to play a dangerous game to secure the safety of her loved ones. But when her worst fears come true, she must fight back in order to save the person she loves most: her daughter.

When Caroline discovers Celine’s letters tucked away in a closet, she realises that her apartment harbours dark secrets - and that she may have more in common with Celine than she could have ever imagined.