Plot: Is it just a fairy tale, or could a primeval beast lurk in the deep, dark waters of a Scottish lake? Since it was first reported more than 60 years ago, hundreds claim to have witnessed the Loch Ness Monster, while one scientist after another has brought the latest technology to the loch to probe the phenomenon. Twenty-five years after their first, groundbreaking expedition to Loch Ness, NOVA joins two American scientists as they return to Scotland for one last go at Nessie