Superintendent Yakushiji and her subordinate, Assistant Inspector Izumida, head to Okinawa - where several environmentalists have gone missing - to investigate the reclusive JPP founder Ryojin Tadomura. Her rival and fellow Superintendent, Yukiko Muromachi, also arrives to carry out an assignment. They find that the JPP founder's villa has been brought under the control of a mutated species of mangrove trees.