Soriton no Akuma plot
The final showdown! The near future. Beneath the calm seas of Japan, a mysterious shock wave (The Serpent) traps a Taiwanese Navy submarine in a ball of light. As a result, that submarine is destroyed. The Serpent then sets course for a huge man-made city off the coast of Okinawa, Ocean Technopolis. This city is also destroyed and thousands of people are killed. The Hatsusiro, a submarine of the Japanese self-defense force, has secretly pursued The Serpent from the depths of the sea. Unexpectedly, it turns out that the violent shock wave has taken on a living form. No one knows how or why the creature strives for destruction.