Morgan and Hannah are Mirror Walkers who are now married. They are asked to explore an old salt mine, the home of their previous adversary, and-while doing so-blunder into several mirrors that lead to World War I and two other Mirror Walkers, Josephine and Rodney. They also discover a young woman, Esther, who can also travel through the mirrors as long as someone holds her hand, and the five attempt to solve a series of gruesome murders that take...