Lupin seems to suffer from transformation sickness, in which one changes into another, cruel personality, and commits crimes repeatedly, but has absolutely no memory of what happened during that time. After numerous crimes not worthy of the name of Lupin, the man himself, having completely lost his self-confidence, even contemplates taking his own life, in his depression, but due to various factors, cannot succeed at dying. It turns out that someone disguised as Lupin has been committing the crime and conspiring with a doctor to trick the real Lupin into believing that he is suffering from transformation sickness.