The early seasons were fantastic, however the 3rd season was really disappointing, I don't know what happened to them. They wasted a lot of well-written characters and killed them off unnecessarily. The main characters in season two became almost like background characters in the last season; They've built their relationship progressively during season 2 for it to be nothing in the end, lessened the entertaining philosophical clash and didn't give enough screen time for the most important characters. The supposedly protagonist barely spoke at all 'til the very end and gave the most anti-climactic "speech". Not to mention the absolutely useless detective and the lack of research regarding some "major injuries" I won't specify further. This review is mostly for the last season since it was the latest one I've watched and stuck to me last. Including all the seasons for this show, I would give it a higher rating since I can't rate the seasons independently. Just have to forget season 3 existed.