The economic situation is a nightmare: only 20% of the population is employed. The Actives live inside the city. On the fringes, in the Zone, live the Jobless. Separating them is a wall.

In a room with no windows on the eastern coast of Africa, an Englishman, James Moore, is held captive by jihadist fighters. Thousands of miles away on the Greenland Sea, Danielle Flinders prepares to dive in a submersive to the ocean floor. In their confines they are drawn back to the Christmas of the previous year, where a chance encounter on a beach in France led to an intense and enduring romance.