Fly Away Home — Christine Nostlinger

When her family's apartment in Vienna is bombed, Christel Goth and her family lose everything. They are offered the use of a summer villa in the suburbs, and walk there in just the clothes they stand up in. The war is ending, and there is a precarious existence eking out food stores, and anticipating horrors from the oncoming Russian army. But when they come, the worst the soldiers do is get drunk and fire their guns. It's a tense time, and Christel's active curiosity leads her into all sorts of dangerous places.