Loch Ness is 22 miles long, 1.7 miles wide and around 400 feet deep. Yet not once but twice a “find Nessie” tourist boat, fitted with an underwater camera, stumbles across a dead body weighed down to the lake’s floor. That, however, was far from the most implausible event in this mildly entertaining but unlikely cop thriller series. The plot had more twists and turns than a spinning Jenny and more red herrings than Billingsgate fish market. With the dead body count up to five you’d have expected the village to be packed with reporters and TV crews from Helsinki to Tokyo but the media was hardly glimpsed. After several misdirections, the girls in blue eventually trap their serial killer….but you have to strain credulity to its limits.