Coming into a village, surrounded by a forest infested with Kumo (spiders), Usagi goes to an inn to stay the night; though the strange and seemingly organized spiders become more and more of a curious threat. Usagi meets a fellow Ronin, named Sasuke. Sasuke talks to Usagi by name, even though Usagi had not introduced himself. The mysterious Ronin warns Usagi of the spiders, and how they are trapped in this village. Usagi does not believe that. The next morning the wall of the inn is bashed through - with Usagi and Sasuke responding to damage. Sasuke says that this was the work of Spiders -- they had absconded with the daughter of the inn-keepers. Usagi exclaims that spiders could not have done this - to which Sasuke counters that Spider Goblins can. Sasuke has been waiting for the appearance of the spider's leader. Sasuke is a Demon Queller, who hunts and fights demons.
Departing with a group in search of the kidnapped girl, Sasuke and Usagi find a cave where their target lies. Coming into the pitch dark Sasuke demonstrates Maho (Sorcery/Magic) by creating a ball of light. Inside the cave they come upon the leader of the spiders a huge grotesque spider, with the body of demon woman on top, referred to as a Kumo-Onna (Spider Woman). Usagi fight through the monster lead by the Spider Woman, while Sasuke demonstrates more magical skill - making a giant frog appear, which Sasuke rides into battle. Usagi is hit by the venomous spray of the Spider-Woman, and collapses into convulsions from it's effect. Before Usagi lost consciousness Sasuke leapt up and dealt a finishing blow to the Spider-Woman.
Usagi later wakes up at the inn, where the daughter of the inn-keeper is there to greet him, gladdened that he has recovered from his injuries after a few days. She excitedly recounts how she was rescued on the back of a giant frog! Sasuke has already left and moved on.
Usagi is traveling through a wooded area, when the appearance of fox-spirit flying past him brings him to a crying woman, who says her child as been kidnapped. Usagi agrees to go to the rescue, and soon finds himself in over his head. He confronts one Yokai (Haunts/Demons) after another - with his prowess with the sword doing little to overcome the fearsome creatures. Luckily in one difficult encounter, Usagi is saved by Sasuke - who Usagi is surprised to see here. Being a Demon Queller, Usagi thinks this job is more suited to Sasuke's skills - and that he would only be a hinderance against such creatures. Sasuke disagrees - saying that it is Usagi's Karma to be here.
The situation they face is a yearly procession of Yokai, through the mortal world - which takes place every summer. Once ever 100 years, this procession of Yokai seek to take over the world -- but to do so, they would need a living soul to lead them. Sasuke and Usagi are confronted by Yokai of all types, from a one-legged hopping umbrella, to a giant fire-breathing Salamander - which Sasuke is able to dispatch by summoning his giant frog, who eats the foul Salamander. During the commotion, Usagi and Sasuke are separated. Usagi crosses a path leading out of the forest, which the already battle-worn Usagi is temped to take, and leave the situation in Sasuke's hand. True to his Karma, Usagi forgoes that path and joins up again with Sasuke, where they both go to confront the main procession of demons, where the little girl is leading them. Usagi lends all his strength to fighting the many creatures, and is terrified and astonished by the ferocity of his foes. The little girl, also, surprises him - as she transforms into a large demon - the leader of the entire group. Sasuke uses all of his magical might in a decisive strike against the enlarged demon - plunging his sword into it's head - which causes it to explode with light. All the Yokai vanish the explosion.
Usagi is able to awaken a weary and weakened Sasuke - who has lost much of his youthful appearance. He had used much of his life-force to destroy the demon. Usagi questions what about the little girl - to which they discover she did not actually exist. The woman Usagi meet on the road had not been real - as both the woman and child where based on the lost family Sasuke once had, many ages ago. Sasuke has been alive for a very long time. After the death of their daughter, Sasuke's wife became a demon, and Sasuke himself became what is now.
Before departing, Usagi realizes that if the girl wasn't real, then -- Sasuke stops him short, answering his question "Yes, Usagi. You where to have been that soul."