In the 21st century, zombie viruses swept the world, and the remaining humans had to leave the earth.
Afterwards, it turned out that all this was a conspiracy, and humans could not return to Earth. In this way, I was born.
Traveling back to before the end of the world begins, preventing the conspiracy from happening, and saving the earth. This is the purpose of my existence.
However, I met him and understood the emotions beyond the mission, which made people feel nostalgic.
But when the man said to me, "If history changes, will you disappear?" I hesitated.
Was it a mistake to fall in love with him that made me forget my mission, forget... The meaning of my existence?