A strange disturbance in Tokyo upturns the ground and shakes the buildings as if something huge is moving beneath the foundations of the city. In the canal of the Imperial Palace, a large tentacle-like vine called Juran appears, frightening passersby. Following this incident, Jun, Ippei and Yuriko witness an underground attack on humans, as the vines try to suck blood from their victims. Dr. Ichinotani suspects that a giant plant has taken root beneath Tokyo.