As our ship starts to sink, I see flares lighting up the midnight sky. 'Hold on tight. I will keep you safe. I promise,' I say to my terrified little sister as I hold back my tears. But I know I can't hold on for much longer and as she slips away, my heart breaks. Will I ever see her again?

England, 1942. On a dark night of the Blitz, Ruby returns to her beloved hometown with her heart shattered. Tears sting her eyes as she remembers the Nazis sinking their ship, and her little sister Eliza drifting away from her on the dark sea. It was their one chance of escape and it cost Ruby so much to leave behind her fiancé Antoine. She's devastated that she couldn't keep the promise she made to her dying mother—to keep her little sister safe.

When Ruby finds her family home destroyed, she falls to her knees in tears. The Germans have taken everything from her—first her family, and now her home. Among the ruins of her life, she wonders if she has the strength to carry on. But then, she finds a mysterious note.

Eliza is alive. I've seen her. You must find her . . .

A flicker of hope is ignited in her heart, and Ruby vows to never give up looking for Eliza. But her newfound courage is put to the test when a message from Antoine reveals something about Eliza's fate that changes everything. She must find him again to learn the truth, but with England at war, will they find their way back to each other? And will she ever see her little sister again?