Atmospheric thriller set in the French countryside. Two British nurses, Jane (Pamela Franklin) and Cathy (Michele Dotrice), take a cycling holiday through France, but end up quarrelling and taking separate routes. Racked with guilt, the more responsible of the two decides to return to the lonely stretch of road where they last saw each other. When there's no sign of her friend, she begins an increasingly desperate search for answers among the reluctant, elusive locals. With darkness falling, her fears for her friend, combined with a growing feeling of menace, threaten to overwhelm her.