A deadly virus has arrived in England from France. The King of Flagg, a city at the top of a hill, locks the gates and nobody can enter or leave. Inside Flagg are the old people and children under ten. The rest of the population is abandoned outside. Ten years later, there isn’t enough food inside Flagg and the people are hungry. Some teens want to get out of Flagg to find food. But the ‘outside’ is unknown. What dangers will they find there? And will they survive on the outside?