|>>|| No. 23645
It's one of the most impressive series I've ever seen. And I say that as a person on the internet.
3 seasons carefully planned and tied up with no stretch, writing with a concerted effort to make things as tight as possible, a novel view of time travel which I've not seen in anything else (future dictates past), and some incredibly immersive casting alongside a wonderful soundtrack.
The story starts with children going missing within a small yet large town, and the suicide of the father of the protagonist. These events drive the mystery, and it's quite meaty. More importantly, it's very satisfying. It is very prone to spoilers, but mainly due to perspective - it is very interesting to watch it again with full knowledge, and quite rewarding. And for that reason I'm really looking forward to ignoring it for 10+ years and going again. I'm watching it for a second time in a few months, and it's nice to have forgotten some details but still know what to look for.
The official website is great, though I didn't find it until I'd finished. It will ask you what episode you are on, and only provide you with information you've already viewed (and forgotten).
The flaws you may notice are the moody tone of dialogue with oddly long pauses, and also a few contrivances to drive the plot, such as miscommunications. It is not perfect, but it is quite unique.