This is a traditional four-person family: a working dad, a housewife, an older sister and a younger brother (and a cat). One day dad has to go out to work for a week, so the house is left with three helpless souls. Of course those little star-shaped akumas (devils) are coming to take advantage, and you, as the mamorigami (protection god) will have to make sure they have a peaceful life before dad comes back.

[Slightly edited from Anime Densetsu]