Zazie comes back after having lost important letters, and he's injured, too.  As the rumor goes around that Zazie threw away the letters in order to escape from the gaichuu, another Letter Bee is to be dispatched from the Bee-Hive to recover the letters and finish the delivery. Lag jumps in to volunteer, but it seems that Zazie braved a dangerous route spotted with gaichuu territories.
I know already, okay?