 The disturbances are originally thought to be aftershocks left over from a supposed massive earthquake on the Kanto Fault that occurred two years previously, causing hundreds of thousands of casualties and several hundred billion dollars in damage (possibly referencing the real-life Fukuoka earthquake or the Miyagi earthquake), although careful analysis of the evidence suggests otherwise.As time goes on, all of Tokyo begins to suffer from abnormal earth tremors similar to those registered in 2005.The tremors are found not to be caused by an earthquake, but by a gigantic octopus that has been dormant for centuries.