During middle Heian Period the country became unsettled with long rain, plagues, and widespread looting. The gate of Rashomon, which was once beautiful and shining, fell apart. Dead people were left there. People said that demons haunted this desolate place.

 Watanabe no Tsuna lived near Rashomon. Tsuna had hidden the demon's arm in his house after cutting it off. The demon's name was Ibaragidoji. Shutendoji, demon chief, felt sorry for his henchman, Ibaragidoji, and went to Tsuna's house to get the arm back. He had killed Tsuna's nanny, Shiratae and disguised himself as the nanny.

The disguised demon chief grabbed the demon's arm. Tsuna fought against the demon with Minamoto no Raiko's help. The demons used witchcraft and flew back to their base, Ohe-yama.