Tegami Bachi, Vol. 10

A New York Times best-selling sci-fi fantasy series with heart.
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.
With Lag out sick, Aria Link, second in command at the Beehive, takes over the job of delivering his letters. But even with Niche at her side, Aria finds that Amberground has become a dangerous place. Can she defend herself armed with nothing but a violin? Meanwhile, Lag’s illness takes a strange turn...