Books in the The Ballad of Lyuba and Ivan series

Darya and Oliivia's year abroad is indefinitely extended when the Nazis invade and occupy France. Their loved ones enlist as soon as possible, but winning the war isn't an easy proposition, and there's no guarantee they'll find Darya and Oliivia, particularly after word reaches them that they were taken away in November 1942

As the world settles down, the Konevs and their friends struggle to come to terms with what they survived and try to become somewhat normal again. However, that's easier said than done when life has changed so radically. Will the Konevs ever find their way out of this endless journey through a dark forest?