While napping on a large rock, Shuten-Dōji is suddenly awoken by a little boy who claims that the rock belongs to him. This marks the start of their friendship. Their friendship is cut short when Shuten-Dōji finds a large crowd outside of the boy’s house. The crowd claims that the boy and his family have been infected and no one dares to go in and check on them. Shuten-Dōji musters up his courage and walks in, only to find Shun and his mother dead surrounded by some strange creatures. Will Shuten-Dōji be able to avenge Shun and his mother and defeat the creature who killed them or will the danger he faces be too great?