Orkney twilight

Jim says he's an undercover policeman. His daughter Sam thinks he's a liar. On holiday in Orkney, beneath an endless midsummer sky, Sam spies on Jim as he runs secretive errands across the island. What did he take from the old watchtower on the edge of a cliff? Why is he so interested in Norse mythology? And why does Sam have the eerie feeling that she too is being watched? When Sam finally discovers the truth, it will draw her into a dangerous world of darkness and deception ... An original and haunting thriller about fathers, daughters and the ghosts of the past.