Mutant Poison-Mothla kills two power company workers who discover electricity being re-routed. Meanwhile, Destron captures the father of a young boy, Tsuyoshi, who stumbled upon their outpost. Kazami Shiro arrives to investigate the siphoned power, and finds the boy all alone. Trapped in the valley by Destron, V3 fights Poison-Mothla, but cannot defeat him. Can V3 find the creature's weakness and reunite father and son?