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.

Yoshimasa Hosoya
as John H. Watson (voice)

Ayumu Murase
as Friday (voice)

Akio Otsuka
as M (voice)

Takayuki Sugo
as The One (voice)

Taiten Kusunoki
as Frederick Barnaby (voice)

Kana Hanazawa
as Hadaly Lilith (voice)

Shin-ichiro Miki
as Alexei Karamazov (voice)

Daiki Yamashita
as Nikolai Krasotkin (voice)

Jiro Saito
as Seigo Yamazawa (voice)

Koji Ishii
as Ulysses Grant (voice)