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Set in a dreary port town in 1970, the story revolves around a group of boys led by the older Kameoka (Kohei Kiyasu) who form their own exploration group. One day Kameoka meets a strange man named Hachiya (Takeshi Nadagi) who works at the local amusement park. Hachiya is convinced a vision of the future he experienced is real, and one day he will have to fight a giant monster called Demeking to stop it from destroying Tokyo. When the time comes, Hachiya suddenly up and leaves. However, with the guidance of a note he leaves behind, Kameoka and his friends set off on an adventure to discover the true nature of Demeking.
Official site
Thanks to Avery