The deeply scary”(BBC Focus) new novel from a national bestselling and critically acclaimed author. Four hostages are rescued from a group of religious extremists in Barcelona. After five years of being held captive together, they make a vow to always watch out for one another. But they never expected this… The world they have returned to has been transformed by water—and the water is rising. As it continues to flow from the earth’s mantle, entire countries disappear. High ground becomes a precious commodity. And finally, the dreadful truth is revealed: before fifty years have passed, there will be nowhere left to run...