Peach Pluck

From Dan of Population GO:
An island was recently discovered off the coast of Japan. This island was mysteriously full of young men and women who lived as though they were in medieval Japan. The Japanese government immediately went to work enrolling them into modern Japanese schools. But not all is as it seems with these islanders. Could they all be descendents of the yokai expelled by the fabled Momotarou? Nahh, couldn't be.