Tegami Bachi: Letter Bee

A person spotted Noir up in the northern reaches of Yodaka. Lag is ordered by the Bee-Hive Master Largo Lloyd to find out what Noir is up to, and he heads there with Niche and Steak. There he discovers a shell of what looks like a giant gaichuu, as well as a used cartridge which Noir left behind. Lag shoots his own shindan into the cartridge!