Nightfall

In 1884, in a history very different from our own, the world stood on the verge of war. Once again, the Russian and British Empires faced each other across the Mississippi. Then the first trans-temporal portal was developed on the Nayarit Line and history changed - again.
A hundred years later the Cross-Temporal Empire consisted of fifty-four parallel, alternate Earths. The death of First Leader Manek splits the ruling Council, and the Clemhorn family finds itself drawn into the struggle. A struggle not only for the future of the Empire, but for their lives; in a war that will split families and set cousin against cousin.
"The first novel in what promises to be an epic multivolume series" - Michael Cnudde (author of War Plan Crimson, A Novel of Alternate History)
"'Nightfall' is a combination of classic sci-fi invasion and imperial literature with a compelling plot" - Jo Niederhoff, The San Francisco Book Review