Tegami Bachi: Letter Bee

Two inspectors from the capital, Akatsuki, come to the Bee Hive. Caribs Garrard and his dingo, Hazle Valentine. They came to investigate a string of letter robberies happening to the south. During one of them, Moc Sullivan is attacked, and the letters he was carrying fall into a ravine. Garrard suspects that there's someone on the inside for Reverse, since they know so much about the Letter Bee's routes and movements, so he forbids them from going to the south. However, one of the letters Moc was carrying was a letter from a sick girl that Lag dictated for her...