Inspired by the Flannan Isle mystery. A small relief boat approaches the Isle, a tiny isolated island no bigger than a football pitch, 20 miles off a rugged coast. Its aim is to routinely replace the three lighthouse keepers, after 6 weeks alone manning the light. It nears the dock and none of the men greet them. The winch is broken. A call. Nothing. Experienced keepers Thomas, James and Donald have vanished. The lamps are clean and refilled; the table is laid for dinner. There is an upturned chair. Two sets of yellow oilskins are missing...The men were never found.