What if the one person who completes you is the one person who can destroy you? For a New Atlantean, finding the one person who is their 'Key' or 'soulmate' means coming fully back to life after hundreds of years of peaceful numbness. But the love that can regenerate them can also destroy them. When Retriever, Kat Kent, thinks she's found her Key in anti-Nazi activist, Kurt Luff, in 1942 she soon realises that having a Key can be a dangerous situation. If she can't save his life she will lose her own. And coming back to life means confronting her own demons, especially when she realises her heart belongs to someone else. For young Bart Lublin, falling in love with a woman he can't have becomes even more torturous when he discovers that the only way he can keep Kat alive is if he can stop Luff sacrificing his own life.