Testa is a young university professor and linguistic genius who can learn any language. His senior, Sergeant Rossa, introduces him to the Allied Cryptanalysis Department, where he is assigned to break the Luger Code, a cipher the werewolves, enemies of humanity, use to encrypt their radio transmissions. Testa is stunned to find that the code sounds like nothing more than a wolf's howl, and his research goes nowhere. He decides to capture a living werewolf so he can study the code more closely, and after exhausting every other option he finally finds one, a female werewolf named Yonaga. The single-episode ONA mixes action and fantasy.