Sawada Tsunayoshi did not expect to meet the creature who was said to be the culprit of the moon's explosion, nor the fact that the creature is also threatening the safety of Earth. Entering his last year in Kunugigaoka with the memories of his counterpart from another life, he might have more than one mission to do in order to save Earth and those he thinks needed some saving.

'You are not a hero.' He grew up as an important figure with that as an advice. He was taught to survive, lead his family and act in accordance to what he think is right. He was taught to save as many people as he could, not save the whole world, and always see the reason behind actions. And that's what he does. Not to be a villain, a hero, or even be normal. Be a Vigilante.