Letter and Letter Bee (chapter) is the 1st overall chapter of the Tegami Bachi Manga.
Note: This chapter is very long, and therefore, this is just a survey that is not exhaustive, but will be a long read.
Gauche Suede begins his journey searching for Lag Seeing to obtain the letter he is to deliver. Soon, Roda, Gauche's Dingo, spotted the chained up boy to a post on a hill. Gauche realizes that Lag is the letter, and decides to take a break.
Lag soon awakens, in shock that someone is observing him, therefore, he becomes scared that Gauche could be part of the group that kidnapped his mother (Anne Seeing) looking for "that light." Gauche attempts to calm the boy down, and gives him soup.
After that, Gauche explains to Lag what it means be a Letter Bee. Letter Bees or just "Bees" must face danger as they venture in delivery of letters to customers. Soon, Lag is identified as a letter with adequate postage. Gauche then begins the descent with Lag to "Miss Mary Sabrina, Yodaka District: Southern Region 624137-22, 109 Cambel Litus." The deliverer of the "letter" is Anne Seeing.
Next, Gauche explains what gaichuu are to Lag, as they are extremely ferocious and dangerous, and live in the darkness between towns. Gaichuu tend to attack when they sense people's "heart." Next thing they know, Gaichuu Daikiri, and then Roda begins the combo attack where she acts as a decoy distraction for the gaichuu while Gauche aims for openings at the joints.
Gauche shows Lag what the Shindan and Shindanjuu are all about, as shindanjuu is "heart-bullet gun," and shindan is, "heart bullet." Lag notices the stone glowing in the shindanjuu when Gauche is about to shoot, and thinks about his spirit amber inside of his eye. Soon, Gauche releases Kurobari (black needle), his technique, as it executes the gaichuu.
Soon, they have soup again, and Lag comments how disgusting it is, including Roda thinking it disgusting. Gauche doesn't realize that Sylvette's soup is gross to other people, as he is probably used to it. Lag and Gauche go on to discuss his gun, as he says he fires out, "fragments of my own heart." He says the only way to defeat gaichuu is to make the "heart" inside that armor cry out (which is likely why Lag thought earlier that the gaichuu defeated had cried).
He explains that the gaichuus do not have a heart, but that they have captured the heart (we can presume via Gaichuu Ropes) and held it captive. The spirit amber inside of a shindanjuu comes from spirit insects' energy, which was materialized by the Land's spiritual energy, and that the spirit insect had locked up in resin, because they possessed this spiritual energy. When changed, that becomes spirit amber overall.
Lag appears confused, as he tries to explain that with the power of spirit amber, "heart" can be used to defeat gaichuu, and that heart decreases every time it is used. Heart can recover through resting periods; however, if all is shot out, especially at once before resting or recovering, the identity of the person is lost leaving only the physical body.
Lag snatches Gauche's shindanjuu and thinks if he had such a gun, he could've protected his mother with it. Soon, the gun charges up, and Lag tosses it. Memories appear of when his mother was taken, to which, Lag soon collapses from exhaustion. Gauche contemplates on firing his shindan into Lag, and does so hoping it would help (not hurt) the young boy. This causes Lag to see Gauche's memories, especially back when he was with Aria Link in Rengus Village, as well as when he promised his sister, Sylvette Suede, that he would make much money when he becomes a Bee, especially a Head Bee—which only saddens Sylvette. The memory concludes.
After he awakens, the two of them set off. Lag asks a few questions, such as about who the Head Bee is, or who Sylvette and Aria are, etc. Lag believes that Gauche will become a Head Bee (the highest ranking among Bees, the boss; there's no letter he cannot deliver), just as Mrs. Speedwell from the bakery (presumably Rengus Village bakery). Lag and Gauche then fish together, as Gauche realizes his memories have been recognized by Lag.
As they bed down, Gauche mentions that letters contain the "heart" of those writing them—where even one word would do. Lag then cries to Gauche; wishing to go to Akatsuki with him; however, Lag would be prevented from crossing Bifrost Bridge since he doesn't have a crossing permit to do so. After arguing a bit more, and being time for bed, Lag takes off with Gauche's gun.
Soon, Gaichuu Bucker pops up from the ground; trying to hurt Lag; however, Gauche and Roda show up to save him. As they are trying to figure out how to shoot the gaichuu, Lag's eye charges—to Gauche's shock—and he was able to shoot a shindan with Gauche's help. This destroys Gaichuu Bucker.
Memories are recalled that Lag received that spirit amber in his eye for protection so he could live (and Lag later reveals to Gauche that it was to cure an illness he had after he was born). Gauche collapses from exhaustion, and when he awoke, he was in Mary Sabrina's house. Lag had dragged him all the way to her house in Cambel Litus.
Mary had soon become angry, because Gauche only asked for a signature on the package, but did not thank Lag for saving his life. He was quickly whisked out, to which, the townspeople didn't even make him feel "welcome." Lag is soon seen bringing Gauche food and water, as he is leaving, saying it's from his Aunt Sabrina.
Gauche then calls Lag a friend, as the delivery is complete, and comments on Lag's bravery, and that he is a man now. They say goodbye, as Gauche heads out the gate. He tells Gauche about the stone embedded in his eye, to which, Gauche made a promise that he would try to find out about Lag's mother someday. Lag says to Gauche that he, one day, would like to become a Letter Bee just like him.
The chapter concludes showing Lag, five years later, as he heads out to take the Letter Bee Examination: