When Lise Becks becomes obsessed with proving the existence of the Loch Ness Monster to validate her grandfather's childhood encounter, she leads a scientific expedition to finally find evidence that will unravel the creature's enduring legend. But as the crew's faith falters after months with no breakthroughs, Lise ventures alone into perilous depths on a rogue dive. When she disappears beneath the waves after recovering mysterious footage, her devastated team is left wondering if their quest led Lise to become the loch’s latest victim – or if its secrets should remain forever unsolved.