After the Armor Heroes united to seal up the Dark Forces Monsters, the city regained its peace and happiness. Since Monster Ten was not successfully sealed up, Mei Zhen found Zi Yang, hoping that when danger and difficulty arises, Zi Yang would be able to seal up this last monster and would completely eradicate the forces of darkness on earth. Meanwhile the Five sealed in the Monster Sealing Box, in order to fulfill their quest for world domination, used the forces of darkness to entice an angry youth, and created new mutants to create havoc in the city.
