STORY

Isamu Wakamura is a typical office worker. He is living with his young daughter Yuko as his wife as passed away. One morning, the bus the two are riding on is attacked by superhuman Jack Flash, who had escaped from a police van. Isamu suffers critical injuries, but his entire body starts to inflate. He becomes superhuman Human-man and puts an end to the crisis. Isamu is perplexed by the change in his body, but after seeing Yuko's excitement about seeing a superhuman of justice, he decides to continue as a superhuman. However, the appearance of his powers was closely related to the massive outbreak of the non-native species Seitaka Awadachi Plant.