Tegami Bachi: Letter Bee

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.

One day Lag Seeing finds himself shipped. His mother abducted by someone, he's now just a package sent by her to be delivered to a friend's house. Gauche Suede is a Letter Bee, a member of the Amberground national postal service, who is tasked with delivering this "letter," together with his partner Roda. The still young Lag rebels at Gauche's seemingly emotionless focus on his work, his heart still reeling from being torn from his mother, but as they head into a valley they are attacked by a ferocious creature known as a Gaichuu.

Lag, having glimpsed into Gauche's heart, comes to know about his dream to be chosen for the highest title the Bee's that work in the capital can obtain, Head Bee, and that he will soon be transferred there, a first step toward that dream. Nearing the end of their journey, one day before reaching their destination Lag and Gauche get in a fight after Lag asks Gauche to take him with him to the capital so he can search for his mother. Angry, Lag takes off with Gauche's shindanjuu and hurries along by himself, but wanders into Gaichuu territory without realizing it and falls into a trap.

Some years after he met Gauche, Lag heads to the main post office in Yuusari to take the interview to become a Letter Bee after passing the preliminary examination. After saying all his goodbyes to the people he loves, he heads to the train station with a Letter Bee named Connor that came to pick him up. But when he arrives, he discovers a small girl hiding herself in a small crevice. And what's more, she's a letter, just like Lag was!

Lag Seeing, who was rescued at a young age by a national postal service worker known as a Letter Bee named Gauche Suede, idolized this Bee and finally met him again after he went missing. However he calls himself the Marauder Noir and steals the letter from Lag. Lag, injured, is saved by the Express Delivery Bee Jiggy Pepper and taken to the Bee Hive, but Lag's partner, his dingo Niche, doesn't take it very well...

Niche thinks she has failed at being Lag's dingo, so she runs away from home with her pet(?) Steak. Worried, Lag and Connor head out to search for Niche. However Niche, hungry and wandering aimlessly around town, sneaks into the bread and weapons shop Sinners and tries to finally cook Steak, but the Gobenis catch her in the act.

One day, while on a delivery to a certain mansion, Lag is asked by Ray Attlee the owner of the mansion, to search for the person who sent a picture-letter to her. Ray says that the pictures in the letters reminded her of her hometown, and gave her the will to continue to live on and fight her illness. Lag, after being called a "Letter Specialist" by Ray, decides not to rely on his shindan that allows him to see the heart contained in letters, and does his best to search for the sender. He discovers that the paints used to paint the letters have some connection to Ray's hometown, and then...