Inevitably, Rachel dropped out just months into her course, and she and Luke moved to Exmouth in Devon. When she died, say her parents, killed by that last injection of lethally pure heroin, she was back on an upward curve. In the last months of her life, she'd begun to write letters to Pauline - long, emotional letters in which she said sorry for what she'd done, and what she'd become. "She was ashamed. She felt guilty and embarrassed, to have put us through what she had. But we thought she was starting to take control again."