Monster: Perfect Edition, Vol. 2 (Kanzenban #2) by Naoki Urasawa (Creator), Camellia Nieh (Translator)

The story begins with the introduction of a new character - Otto Heckel. Otto is a cat burglar and bumps into Tenma when Tenma is investigating the Springer murders. Otto suggests becoming Tenma's manager and making Tenma a famous doctor in the underworld. When they found the killer of the Springer, he confesses his murder to Tenma. He passes the message given by the mastermind that Tenma has been looking for.

Tenma tracks down the adoption history of Johan and Nina. Both used to wander near the Czech border but were later placed in separate facilities. The east orphanage 511 Kinderheim was a "special facility" controlled by the interior ministry. It was the East German government's laboratory to conduct experiments to turn children into the ultimate soldiers. The experiment reprogrammed the orphans and taught them to hate and fight. Before the wall was demolished, all the top-secret documents related to the project were burned. The orphanage fell into anarchy and caused the children and staff to fight against each other.

Both Tenma and Nina find the vital link to Johan, respectively. Tenma is looking for Johan to prove his innocence from a series of murders. Meanwhile, Nina is being used as bait and captured by the neo-Nazis under the command of the group's frontman, "The Baby". The capture of Nina also leads to the exposure of another bigger crime committed by the neo-Nazis. At the same time, Johan leaves a message to Tenma and Nina, making them wonder whether they should believe Johan.