Previously... Events in the Maunsworth Array have led to a resonance in the Standing-Point Field that has hurled Grace and Thomas back into the Heavenfield, but worse, has allowed a terrible creature out into the Array Hall. Stuart Nicks, together with three soldiers, finds himself chasing after the creature in a desperate attempt to prevent it escaping into the Array tunnels, and from there out into the world. Meanwhile, Thomas and Grace have found themselves on the edge of another Heavenfield reality, alone with the Angel, and the approaching armies. The three forces, British, American and Exile, unable to retreat, must defend the open Entry-Point. They cannot allow any more creatures through, and can only dig in and await the inevitable onslaught...