Beyond Loch Ness (2008)

James Murphey is a rugged cryptozoologist, who thirty years earlier, during a trip to Loch Ness, Scotland, had a fatal encounter with the fabled "Nessie" creature that killed his father, and left James with deep facial scar. Twenty years later, James is hunting for Nessie, when his search leads him to the sleepy town of Pike Island, Ashburn, on Lake Superior. Hiring Josh Riley as his guide, James and Josh bond over their mutual scientific interests and deceased fathers, while James tries to convince Josh's mother, Sheriff Karen Riley, that the 60-foot plesiosaur is killing and breeding.

Unfortunately the movie Beyond Loch Ness is not yet available on HBO Max.