You play as Ushio Aotsuki, son of a local monk who is informed by his father of his lineage. For most of his life, his father repeatedly tells him about their ancestor who fought and defeated a man-eating youkai with an enchanted spear called "The Beast Spear". One day, while cleaning the shed, he discovers an old cellar door that he opens at random and finds the youkai inside, skewer on the famous spear. Ushio pulls out the spear