Yes, well, it's not impossible
You are absolutely right, Ellie. There are three books in total. However, books two and three won't see the light of day if the first one doesn't sell enough. Book two is set in North Africa, and book three follows Maria and Katarina as they try to get home through war-torn Europe. I have also begun to write a fourth part, which carries on from the war's end.
I just hope it gets noticed enough for more people to enjoy it. It was very popular when I posted it all here.