How I live Now by Meg Rosoff (2004)
I love this book with all of my little tiny heart. It's YA, and Chinese book info sites list it as a "children's book", and I'll be 50 soon. So, Elizabeth/"Daisy", fifteen, escapes her father and stepmother by travelling to England to live outside London with her real mother's sister's family. Real mother's sister is a bigwig and often not present because everyone's been Living With The Threat Of War for a long while now. In fact, she leaves the day before a series of large explosions cripple London. The war is noticed by Daisy and the cousins only as a loss of electricity, phones, and as time wears on, food. What the movie of this book didn't quite get is it's the characters and the relationships this story is about, along with the roles of privation and plenty.
YA's not for everyone, I suppose, but I liked this one.