In 2016, the Japan Coast Guard investigates an abandoned yacht in Tokyo Bay. The boat is soon destroyed, and the Tokyo Bay Aqua-Line is flooded with blood. After seeing a viral video of the incident, Deputy Chief Cabinet Secretary Rando Yaguchi believes it was caused by a living creature, which is confirmed as news reports reveal its tail emerging from the ocean. Shortly thereafter, the creature moves inland, crawling through the Kamata district and the Shinagawa area of Tokyo, leaving a path of death and destruction during a disorganized and chaotic evacuation. The creature quickly evolves into a bipedal form, but overheats and returns to the sea.