The story takes place in 19th century Europe, and revolves around John Watson. He is scouted by the government to become a secret agent. However, Watson lives in a world where "Frankensteins"—human corpses that are re-purposed with a false soul in order to use them as laborers—are used to improve industrial development.
| Actor | Role |
|---|---|
 Yoshimasa HosoyaJohn H. Watson (voice) | John H. Watson (voice) |
 Ayumu MuraseFriday (voice) | Friday (voice) |
 Akio OtsukaM (voice) | M (voice) |
 Takayuki SugoThe One (voice) | The One (voice) |
 Taiten KusunokiFrederick Barnaby (voice) | Frederick Barnaby (voice) |
 Kana HanazawaHadaly Lilith (voice) | Hadaly Lilith (voice) |
 Shin-ichiro MikiAlexei Karamazov (voice) | Alexei Karamazov (voice) |
 Daiki YamashitaNikolai Krasotkin (voice) | Nikolai Krasotkin (voice) |
 Jiro SaitoSeigo Yamazawa (voice) | Seigo Yamazawa (voice) |
 Koji IshiiUlysses Grant (voice) | Ulysses Grant (voice) |
 Houko KuwashimaMoneypenny (voice) | Moneypenny (voice) |
 Kouji TakedaThomas Edison (voice) | Thomas Edison (voice) |
 Yoshimitsu TakasugiSherlock Holmes (voice) | Sherlock Holmes (voice) |
 Issei FutamataNarrator (voice) | Narrator (voice) |