Top Of The Lake

 Obsessed with the disappearance of a 12-year-old pregnant girl near a freezing lake in New Zealand, a brave detective will find herself up against small-town secrets and a side of herself that was meticulously kept at bay. 

This show has two seasons. The second season was better than the first one.
I didn't have high hopes for this one but it turned out to be a good show. I enjoyed it.
Here's a trailer for season one :