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.