In Brazil to deliver a lecture on diseases that affect memory functions, Dr. Taylor Briggs (Billy Zane) is called upon to consult on the condition of a man found close to death near the upper reaches of the Amazon. A scan indicates a curious anomaly - he has massive tumours in all the areas of the brain used for storing long-term memories. Investigating the man's personal effects in the hope of finding some clues, Briggs comes into contact with a strange orange powder found in the man's rucksack but thinks nothing of it.

However, back at his hotel, he experiences an inexplicable event as the building is hit by a tremor and a tidal wave of water floods the room. Trapped and in danger of drowning, Briggs punches his way through the ceiling but on surfacing is shocked to find himself in the middle of a clear mountain lake surrounded by pines. After making it to the shore, he spots and begins to pursue a dark figure in a long overcoat through the woods, but trips and falls only to find himself back in his pristine hotel room.

Back home in Boston, Briggs is unable to shake the memory of the experience but returns to his work on finding a cure for Alzheimer's Syndrome, a disease that struck his mother and an early age. Disturbingly, the bizarre visions of the shadowy figure continue to haunt him and he realises he is witnessing the crimes of a kidnapper, crimes that were committed years before he was born. Meanwhile, the mystery surrounding the patient in Brazil has been solved.

The man was a geneticist studying an ancient ceremony practised by remote Indians, one that allowed people to access memories of their parents' lives prior to their own birth. Could it be possible that contact with the orange powder has somehow activated within Briggs the actual memories of an ancestor? And if so, what is his connection to the nightmare world of the predator whose evil work he witnesses through his visions?