Twenty years ago, the war between the island nation of Midgard and the continental empire of Oikumena ended in a crushing defeat for the Archipelago. The countries concluded a shaky truce. Now Midgard is saving up strength to take revenge. The military academy trains pilots of "valkyries" - air combat vehicles. Only a few will pass the tough selection... Aldis and Helg are first years. To become the best, they have to fight with peers, with the cunning of mentors and their own fears. But not everything is as simple as it seems at first glance. Which fellow student spies for the Order of the Eye of Heaven? What is the mysterious "berserker"?