In a South Yorkshire city, Ryan Sinclair, Yasmin Khan and Graham O'Brien are about to have their lives changed forever, as a mysterious woman, unable to remember her own name, falls from the night sky. Can they believe a word she says? And can she help solve the strange events taking place across the city?

　　本片有着令人胆战心惊的剧情，其故事来源于一个臭名昭著的真实罪行，Ian Brady 和 Myra Hindley 两人在60年代中期绑架并杀害了5人，三名儿童和两名青年，其中四人被埋在约克郡的沼泽里。