Ookami Kakushi

Ookami Kakushi is a great mystery anime series. The first episode is just everyday happenings and yet is one of the creepiest I've ever seen. You are left feeling that something is not right. It is one of the few times I've been completely hooked on a series after only the first episode. I won't spoil the mystery but it is completely resolved by the end of the series. However, there are more story possibilities which suggests there may a second season anyway.