Late one Friday evening, Sarah de Lagarde was heading home from work. She decided against a taxi and made for the tube. Tired after a long week, looking forward to seeing her daughters, she nodded off on the train, and, on waking up, blearily got off. She was at the wrong stop. As she turned round, and made to get back on the train, she slipped between the door and the platform, and landed on the tracks. . .

This is the story of how quickly life can change, all in the blink of an eye.