The story takes place in the land of Amber Ground, a place of perpetual night only partially illuminated by an artificial sun. Lag Seeing works as a "Letter Bee" (delivery boy) at the "Bee Hive" (a delivery service), with his Dingo, Niche, and her "pet," Steak, traveling with him. He is entrusted with the "hearts" of the everyone in Amber Ground to deliver their packages.
[Source: Wikipedia]
Apparently abandoned by his mother, orphan Lag Seeing is taken as a "letter" by "Letter Bee" Gauche Suede to a town where his aunt raises him. His affection and admiration for Gauche give Lag the ambition to become a Letter Bee himself, carrying mail through the dangerous wasteland between towns on his world. When he becomes a teenager, he makes the trip to the capital to take the examination to become a trainee Letter Bee. En route, he meets the strange, powerful girl-like creature Niche, who becomes his "dingo," a Letter Bee's travelling companion. Lag yearns to find his mother, and discover why she abandoned him, if she did.
[Source: Anime News Network]
After Niche carries the wounded and stunned Lag back to the Bee Hive, the Letter Bee finally begins to piece the puzzle together. Now he knows what's happened to Gauche, why the Marauders are so focused on stealing mail and the actual intent of the group controlling both, Reverse. However, when he's forbidden to reveal the truth, Lag is soon forced out of the artificial sunlight and back into the world of perpetual night. And soon Reverse's plot to take down the Letter Bees and overthrow the Amberground government begins to accelerate. If things weren't already bad enough, the giant insect creatures called gaichuu are apparently evolving into something new; there may be traitors working within the Hive; and Niche's sister, who's definitely not human friendly, shows up to turn family drama into a full-scale siege! It all spells serious trouble for the Letter Bees, but if anyone can weather the storms and gloom of night, Lag and his team are the ones who'll deliver.
[Source: FUNimation]
