This is probably few of those hidden gems that doesn't get the highlight it needed. if you haven't watch it yet i suggest you do as the story and mystery will keep you compel to continue with all the question of who what when where and why. being an original work is very interesting to see as the current anime trend is based on light novel to driven the sales of the product and most of this light novel anime won't even have a 2nd season due to the fact you wanna know what happen read the novel. highly recommended if you like sci fi andmystery