A group of researchers sets sail for the Isle of Dorn in the North Atlantic in 1905 to explore the cause of several mysterious disappearances, most notably a family of four who vanished without a trace after a week-long holiday on the island. Led by Professor James, a prominent member of the Society for Psychical Research, they begin to explore the island's sole cottage and surrounding landscape in search of a logical explanation. The idyllic setting belies an undercurrent of danger and treachery, with raging storms and unnerving discoveries adding to the sense of menace. As increasingly unexplainable events unfold, the now-stranded investigators are unsure whether they can trust their own eyes, their instincts, one another, or even themselves.