Life is good for Anna Wright. She's a successful media executive working for one of the UK's largest TV corporations. She's got a great boyfriend, some close friends and a lovely home. She adores her dog, Wispa, and she loves to run to help her de-stress.But Anna's perfect life starts to crumble from the moment when, out jogging on the Heath one day, she meets a handsome stranger. She takes a route into unfamiliar territory, and then she has to face the consequences. There's a dark, growing creepiness as the atmosphere becomes unsettled and, as Anna's professional life becomes increasingly pressured and poisonous, her obsession with the intriguing stranger intensifies.