One day, Mana and her mother go to visit Toshiko, Mana's hospitalized great aunt. When they arrived at the hospital, Toshiko asked if they could check on the flowers at her home. When they reached the house, Mana was surprised by the sight. Bright red flowers were in bloom everywhere; from the garden to the walls and the roof of the house. Mana sent pictures of these mysterious flowers to Neko-Musume. While Mana listened to stories about her great aunt from her mother, Kitarō and the others soon arrived. Medama-Oyaji explained that these flowers were called Yōka and bloom from yōkai activity or spiritual power. Why are they at Toshiko's house? Mana joins Kitarō and the others as the head toward a southern island to discover the Yōka's origins.