When both his holiday plans and love affair collapse, London doctor Charles Mackinnon agrees to act as locum in Skye, looking forward to a peaceful stay. However, within hours of his arrival he witnesses someone being thrown off a distant cliff into the sea.

When the body of Jamie Gillespie is discovered in the water, the police remain sceptical of his report, and he begins to doubt what he saw. Then a pregnant, disabled woman disappears, and Charles finds himself drawn into a primitive ritual of superstition and violence.