Tegamibachi: Hikari to Ao no Gensou Yawa

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)Letter Bees risk their lives to deliver the "heart" contained in letters. One day, newbie Lag is asked by the Bee Hive supervisor to deliver something to a girl named Elena. He's introduced to Darwin, who will guide him to his destination, and sets off in good spirits with Niche, but...!?