After Niche returns the injured and shocked Lag to the Bee Hive, the Letter Bee begins to put the jigsaw together. Now he understands what happened to Gauche, why the Marauders are so bent on stealing mail, and the true aim of the group controlling both, Reverse. When he is banned from revealing the truth, Lag is quickly dragged out of the artificial brightness and back into the realm of eternal gloom. And Reverse's scheme to depose the Letter Bees and overturn the Amberground government picks more steam. As if things weren't awful enough, the huge insect monsters known as gaichuu are reportedly developing into something new; there may be traitors among the Hive's ranks; and Niche's sister, who is unquestionably not human.