At first glance, the couple on the train look normal. She's dressed smartly, a floral-patterned bag on her lap. But her hands are clenched, her fingers white. The man with her has his arm looped through hers, but not in a comforting way. He's holding her too tightly. She catches my eye and I see desperation there. I'm opening my mouth to speak when the train grinds to a halt and the man stands, hauling her away. She looks at me again, then at the seat behind her, her face pale. I find the message she left behind. Help me. When I call the police, there's no sign of the couple on CCTV. The kind detective gently suggests that it's not surprising, with my history, that I am imagining things. Wanting to save someone. I know what I saw. If no one will believe me, I'll find her myself.