"The Killing "(AMC, Sundays). That "The Killing" would return was not at all clear at the end of its previous season; viewers grumbled that two seasons was too long to follow a case that in the context of the series took only as many days to resolve as there were episodes. (It did create a kind of temporal cognitive dissonance, to be sure; and yet I was even more of a fan in the series' second season than during its first.) Beyond the crime the title requires, and first and foremost, "The Killing" concerns two troubled, fatefully entwined detectives -- Mireille Enos as Sarah Linden, who cares too much, and Joel Kinnaman as Stephen Holder, who also cares too much -- working in a Seattle so wet and rainy as to suggest a city less of the Pacific Northwest than the post-apocalypse. (It's Vancouver, actually.) Based on a Danish series, it was a herald of the slow and steady, mood-first style we've seen here more lately in "Top of the Lake" (its twin in several respects) and "Rectify." As in the first season (and as in "Lake" and, retrospectively, "Rectify") it's a story of lost children in a cold world, and heroes almost too weary to help them, but helpless not to try.