Alongside the pleasures of watching the first four wonderful seasons of “Shetland” has been a regret that I’ve not read any Ann Cleeves, the mystery author of the underlying books. I’ve begun to redress that omission with her non-Shetland series but in the meantime Season 5 of Shetland has popped up, and wow, this season takes the show to another level altogether. From the opening scene of DI Jimmy Perez and his trusty offsider Tosh inspecting grisly remains washed up on a beach, what grips the viewer is the galvanic intensity of Douglas Henshall in the leading role. This case obsesses Perez and we see it in Henshall’s drawn face, his posture, his movements. As in the previous seasons, the direction is brilliant, the Shetland scenics are spectacular, and the script’s episode-by-episode plot is as tense as. Season 5 is a rollercoaster of thrilling viewing. I know Ann Cleeves has ended her Shetland books, here’s hoping Perez lives on in further onscreen seasons.