London, 1974. As Britain prepares for electrical blackouts to sweep across the country, trainee nurse Val arrives for her first day at the crumbling East London Royal Infirmary. With most of the patients and staff evacuated to another hospital, Val is forced to work the night shift, finding herself in a dark, near empty building. Within these walls lies a deadly secret, forcing Val to face both her own traumatic past and deepest fears.
Tomaz, an ex-soldier now homeless in London, is offered a place to stay at a decaying house, inhabited by a young woman and her dying mother. As he starts to fall for Magda, Tomaz cannot ignore his suspicion that something insidious might also be living alongside them.