Under A Fallen Sky: From the ashes of Konigsberg. Under A Fallen Sky, #1

Before the sirens, there was the scent of sizzling bacon and the warmth of the East Prussian sun. For young Johan Kuhn and his secret brotherhood of boys, the city's avenues were a kingdom. They were Teutonic Knights, vanquishers of beasts, and guardians of the road to Jerusalem. And at the center of it all was Erika-the girl who held his heart and a promise he was determined to keep. Johan's father is a high-ranking officer in the Waffen-SS and is charged with defending the city.
After realizing that the city has fallen, he decides to move his family away from the devastation and towards the coast, where all manner of ships are designated to move German civilians and soldiers back to the safety of German soil. Along the way, he is executed, along with his wife and others, leaving behind Johan, his sister, and two other orphans to fend for themselves in the wild, dark forests of East Prussia.
But the Reich's pride is a fragile thing. When "they" arrive, the games of childhood vanish in the smoke of a world on fire. As the shadows of war eclipse the radiance of his youth, he must discover what remains when a flawless world is torn apart.