私家侦探Tommy Akhtar （里兹·阿迈德）在追查失踪俄国妓女的过程中发掘出一连串暗黑秘密，也牵扯出了关于自己和伦敦这座城市的不堪真相。这部犯罪悬疑电影根据Patrick Neate的小说改编，由BBC和BFI联合出品。

　　艾薇（朱迪·科默 Jodie Comer 饰）有着一段悲惨的过去，她曾经被人囚禁在地窖之中，长达十三年之久。十三年后，艾薇终于逃出魔窟，报警求援，艾利尔特（理查德·兰金 Richard Rankin 饰）和搭档丽莎（瓦伦·凯恩 Valene Kane 饰）受理了此案，他们想从艾薇的口中获取更多的线索，然而，艾薇的证言仍旧缺少着最有力的支持，那就是确凿的证据。
　　除了要应付警方的讯问，艾薇还必须面对自己内心的黑暗和社会的扭曲与不公，更重要的是，她不知该以怎样的姿态，回到阔别已久的家庭之中。一位名为菲比（Isabel Shanahan 饰）的十岁女孩的失踪吸引了警方的注意，目击者将矛头指向了名为马克（彼得·麦克唐纳德 Peter McDonald 饰）的男子。

　　When 10-year old Olivia's Mom goes on a business trip for the weekend, she leaves Olivia home alone with her 17-year-old brother Miles in charge. The first night, Olivia falls asleep on the couch, and wakes up, not realizing how late it is. She walks her dog Charlie without Miles knowing, and witnesses a young woman being kidnapped on the empty New York City streets. Olivia runs home and tells Miles, but he doesn't believe her. The next morning, she explains what happened to local cops, and they don't believe her either! Only a cynical female detective named Dottie (played by Academy Award winner Susan Sarandon) listens to Olivia, but she too is skeptical. Undaunted, Olivia bravely launches her own investigation, putting herself into perilous situations. Her can-do spirit ignites one extraordinary adventure after another. Can she outwit the bad guys and convince her brother and Dottie of the truth in time to save the day?