Story
Last summer. Friends. And Kaiju. In the summer of 1989, sixth graders Boko, Joe, and Junichi are on their last summer vacation as elementary school students. As if to cut through their daily routine, a monster named Gyaos suddenly attacks Tokyo. The four are petrified in midst of a town turned to ruins. As Gyaos sets its sight on them, a huge turtle-shaped kaiju appears in front of the boys. Its name is Gamera. Despite its injuries, Gamera fights Gyaos with all its might. This would only mark the beginning of the boys' "Summer of Kaiju".
Synopsis via AniList (English).
