One day Mai Katamoto, a female college student who was chewing on a hot meat bun in a park on a cold day. Suddenly a cute cat approached her, and the cat said, "I finally met you!" in clear Japanese. Mai, who is frightened, tries to get away from the scene at a glance, but the cat tells her the truth and stops. At this time, no one knew that the encounter between these two would lead to the invasion of the Earth from aliens.