Kyojuro is a member of a secret association that investigates and solves supernatural mysteries, protecting people from ghosts and demons. For the past few months, in the town of Baalángel, there have been a series of strange disappearances every new moon and no one in the town can explain why this happens. So Kyojuro goes to the place to obtain information; However, the inhabitants are too secretive towards outsiders. Therefore, Gyomei, leader of the association, assigns him a covert mission:

Kyojuro must infiltrate the local convent by posing as a nun named 'Umalia'.

The thing is: Kyojuro is too striking to go unnoticed, so she must make an effort to appear to be a sweet and devout nun in the eyes of the other sisters of the convent, at the same time, discovering and eliminating the being that terrorizes the town.

For your part, you are a young nun who was born and raised in Baalángel. A couple of weeks have passed since the arrival of 'Umalia' and you suspect that she is hiding something. After you were left alone in the convent courtyard, you decide to confront her and discover the truth about Kyojuro. Seeing the situation, you decide to take advantage by proposing a deal:

You will keep his mission a secret, as long as he includes you in his investigation, he helps you leave the convent and leave that forgotten town forever.