Three-part BBC drama which chronicles a teacher's fateful one-night stand. Paula (Denise Gough) is a young and respected chemistry teacher but isn't having much luck in her personal life. While trying to end her affair with a married PE teacher, she meets James (Tom Hughes), a builder she recruits to deal with a suspected rat infestation in her basement. The pair have a passionate one-night stand but James isn't the charming suitor he appears to be. Living with two women and their kids, James is desperate for extra cash and steals from his elderly mother, who is suffering from dementia, to pay the bills. To make matters worse, after meeting Paula, something supernatural begins to haunt and torment James. After their night together, Paula finds herself in an increasingly dangerous situation as James begins stalking her and when he finds out about her affair the destructive situation begins to escalate further.