Test your logline here before spending months in development. This is not a contest, there are no prizes. However, you WILL get invaluable help in sharpening your concept and refining your logline. Make sure to start here.
I’m aware of possession by demons in Catholic theology (I assume the priest is Catholic), but I’m not aware of possession by another person, in this case a boy possessed by a girl. Please clarify what that is supposed to mean.