Yuuki discovers on his eighteenth birthday that he's the last of a dead species, born from a father who was supposed to be the chosen one. The film doesn't celebrate this reveal, it uses it to ask whether heroism even means anything when the world has already decided who matters. The gap between what Yuuki was supposed to be and what he actually is becomes the only story that counts.
The year 22XX brings humanity to the brink of extinction. Desperate to survive, the government opens its borders to allied worlds, and genetic interbreeding produces humans bearing supernatural gifts. Yuuki discovers on his eighteenth birthday that he carries dual heritage: his father belongs to the celebrated "hero" bloodline, while his mother comes from a plant-wielding species thought extinct after centuries of industrialization pushed nature to the margins. This collision of bloodlines grants Yuuki extraordinary abilities, but also an impossible choice. The hero faction demands loyalty to their vision of progress and strength. His mother's people, fragmented and hidden, need him to remember what the world tried to destroy. As Yuuki grapples with his dual identity, he confronts a harder truth: heroism itself may be a lie told by the victors. His power could rebuild what was lost or cement what already exists. The decision of which world deserves his strength becomes the weight he carries alone.