Entitled "Tegami Bachi: Hikari to Ao no Gensou Yawa"
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...!?