Lauren is an ordinary young woman whose idealistic life is happy and safe. Living with her old-fashioned grandparents, she is trusting to a fault. And why shouldn't she be? Her new boyfriend, Josh, seems perfect and meets with their approval; she loves her job and the daily commute on the train, but all that is about to change. Her naïve expectations of others and her refusal to recognise a lurking danger in her midst plunge her cosy world into chaos that has devastating consequences for everyone...