A strange metallic rock lands outside the home of Agent Ishuguro, one of the Ultra Guard members. Having spent six months in solitude aboard Space Station V3, Ishuguro returns to Earth for vacation. Escorting him home, Moroboshi spies the large, peculiar space rock. Using his telepathic powers, he recognizes it as being from another planet. Later that night, agent Ishuguro transforms into a blood-drinking plant creature. He roams the street killing passersby who eventually come back to life as plant monsters know as Alien Waiell who likewise spread the contagion. (Source: ultra.fandom)