The wanted criminal, Akaboshi Bisco, causes havoc in the town of Imihama using his bow to cause giant mushrooms to bloom. Bisco searches for a doctor who can synthesize medicine to save his mentor, Jabi, who has become gravely ill. Bisco storms into the clinic and accosts Milo, but Governor Kurokawa hears the commotion and dispatches his elite forces.

Bisco is gravely wounded by the shot from Kurokawa. Milo leaves him behind to storm into enemy territory and rescue his captured friends, Pawoo and Jabi, but Kurokawa awaits with meticulously set traps. During their confrontation Kurokawa reveals his great ambition and the secret behind the Mushroom Keeper's persecution.