In a city overrun by war, Luka doesn't have time for games. So when his little sister asks him to care for her faeries as she's sent away to escape the air raids, he dismisses her childishness. But it's already more than he can bear to see her go, so he promises to do as she asks. A promise that Luka quickly breaks. In an empty home, anger and frustration get the better of him. Instead of leaving an offering for the faeries, he flings their saucer of milk as far out the window as he can. Big mistake. The faeries are not only very real, but they're more terrifying than he could have ever imagined. And now they want revenge. With the aid of his new friends—a savvy techie, a quiet evacuee, and an unlikely ally—Luka has three days to turn his house into a fortress. But his problems are even more complicated than he thought: it's not just the faeries who are out to get the Wild Huntsboys ... If Luka fails, those closest to him will pay the price—and time is running out.