Maybe it is mostly based on assumptions, usually, we can't prove it for sure, but it seems that bad karma can be a very serious thing. The relation of cause and effect most of the time is obvious, but it is hard to prove it when it seems that we take the consequences of something done by our ancestors, even though people say that this phenomenon really exists.
Akari, her father, and their whole family face something that can be described as bad luck. Or as they say, they don't have luck in anything. Everything they do seems to be doomed. The reason for that, Akari's family finds in the existence of a certain witch named Nina. This witch lived in the same village as Akari's grandmother, and according to the stories told by some of the members of the family, she is guilty of the bad luck in the family.
Akari and her father have come to the grandmother's village, intending to break Nina's magic, but initially, they have to find the objects used for making that magic.