You think it's a supernatural story? Nope, it tricks you into thinking it's simple, but it's actually a very complicated plot covered in mystery and involves lots of angst. It's super good!
It's imposssible to not love the twins, and the plot it's a lot more interesting that it looks at first. Link to the first season complete: http://spideronthewindow.tumblr.com/post/151664041544/twin-spirit-detective-masterpost-part-1