In the middle of a family visit, a pair of masked children appear before Mai Sahara and beseech her to help their mother in pain. She follows them, only to soon find herself at a shrine deep within the mountains that she is not at all familiar with. Imigo, a resident of the shrine, is less than pleased to see Mai at his dwelling and sends her off, but some mysterious power seems to be keen on keeping her there. Only then does Imigo agree to help Mai find a way to leave the shrine safely, and thus begins their journey, with Mai taking a step towards discovering the truth behind her past.