When 15-year-old Joanna Dennehy first met 20-year-old John Treanor in her hometown of St. Albans, Hertfordshire in the United Kingdom, the romance was like something out of “Trainspotting”. It predictably descended into madness over the course of 12 years, because Joanna had been hiding a secret. It was one that jeopardized the lives of everyone in her orbit.