It begins as a school trip to London. But with a sudden tidal surge and a dramatic thunderstorm that hurls rainwater down on the capital, it suddenly becomes something totally different - the site of a major disaster as the Thames Barrier is breached and London is flooded. With streets underwater, communications down, rats pouring up out of the sewers and thousands of people in a state of panic, survival becomes a very key issue for Ben and his mates. But worse is to come when a high-security prison is evacuated and a vanload of category A prisoners is caught in the torrent...