Amberground is locked in darkness. A man-made star casts only a dim light over the land. The pitch-black wilderness is infested with Gaichuu - colossal insects with metal exoskeletons. The Gaichuu make travel between the cities of Amberground extremely dangerous. But thankfully the Letter Bees, a brave corps of messengers, risk their lives in order to keep the hearts of Amberground connected.<br><br> After years of searching, Zazie is on the trail of the Gaichuu that devoured his parents' hearts. But the hunt will force him to learn more about himself - and his past - than he ever imagined. And Emil, the kindly blind girl who runs the nearby inn, has an terrible secret ...
