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.

On the morning of the first day of work for new Letter Bee, Lag Seeing, and his dingo Niche, the sub-master of the Bee-Hive, Aria Link, stops by Sylvette's house where Lag is now living. She shows him to a place known as the Hill of Prayer, where everything with Gauche had its beginnings.

One day, a trio calling themselves the "Letter Pigeons" barge into the Bee-Hive and challenge the Bees to a race, in order to make a name for themselves and start a letter delivery service besides the Letter Bees. Master Largo thinks it sounds like fun so Lag, Zazie, and Connor take on the Letter Pigeons in a fierce delivery battle!

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...