'Better Call Saul' begins unwrapping the final layers of its mystery

This week brings a second season of "Russian Doll," but in a sense, the true TV version of a Russian nesting doll is "Better Call Saul," deftly adding one more layer each year as it has approached the outer shell that was "Breaking Bad." The beginning of the final season brings the AMC series a few steps closer to its endgame, with tantalizing clues but scant clarity about these final pieces.