Backgainer - Yomigaeru Yuusha-tachi: Kakusei-hen "Gainer Tensei"

At the beginning of the 21st century, although scientifically developed, everyday life continues to be as peaceful as ever. At that time, mysterious incidents such as the disappearance of humans and the appearance of monsters begin to occur here in Japan. The cause was not generally known, and critics treated it in a funny way every day in the press. However, in the shadow, the Metropolitan Police Department special police riot police (commonly known as special riot police) was formed to investigate and resolve this case independently and was active by making full use of humanoid weapons. One day, "Shin" and "Natsumi" who were attending school as usual encountered a traffic blockade by the riot police. The usual quiet morning was disturbed by the news helicopters flying in the sky. What they saw there was a special police shell and a monster jumping out between the buildings. In order to help "Natsumi" who was injured and stuck in the explosion of the news helicopter that was shot down, "Shin" boarded the shell "Ribral" which had been abandoned.