Sentan Island is a small, dreamlike island surrounded by the Yuden Sea, cut off from the war between the Northern Government and the Southern Continent Free Zone. The protagonist, Akiyuki Takehara, lives on the island with his mother Fusa, while his father, the town doctor Ryuzo, remains separated but their bond endures. One day, after taking Ryuzo the lunch that Fusa has made for him as usual, Akiyuki arrives at school, where he and his friends Haru and Furuichi are caught in an explosion. The blast produces a mysterious light that enters Akiyuki's arm, causing him excruciating pain. He has no time to understand what is happening, as the…