Kaname Ōba tends orchids at a secluded estate with his wheelchair-bound sister, cultivating their family's rare "Blue Lady" variety in isolation. Their existence stems from a past incident where their father killed the sister's lover using a bow and arrow, a method repeated over subsequent years. Kaname participates in luring visitors to the property under false pretenses. These individuals are murdered, their remains incinerated, and the resulting ashes used as fertilizer for the orchids, believed to enhance the flowers' growth and rarity. Kaname justifies these acts as necessary to protect his sister and preserve their legacy, covering up the crimes and preventing discovery. When Minako Ifu investigates the estate after her friend's disappearance, Kaname initially attempts to warn her away. Minako's presence, however, leads to the unraveling of their secret. The situation culminates in a confrontation exposing the full extent of the murders and the use of human ashes.