One minute fifteen-year-old Ruby Morris is having her first proper snog with Caspar McCloud in a hot tub, and the next she's being bundled inside the house, dripping wet, cold and in her underwear. As she and Caspar shiver in the kitchen, it starts to rain. And now Ruby is totally alone. People weren't prepared for the rain, got caught out in it, didn't realise that you couldn't drink water from the taps either. Even a single drop of rain could infect your blood, and eat you from the inside out. Ruby knows she has to get to London to find her dad, but she just doesn't know where to start