Based on The Peshawar Lancers by S. M. Stirling, and written by Analytical Engine, it attempts to create a more realistic timeline than the one portrayed in the book. Essentially, it is a re-imagining of sorts. Read it here.
As in The Peshawar Lancers, the PoD is the impacting of cometary fragments upon Europe and North America in 1878. This prompts those who can to evacuate to more hospitable parts of their holdings- for example, France to Algeria, Russia to the fertile region between the Black Sea and the Caspian, Americans to the South and Britain to India, Australia and Southern Africa.
Naturally, this has a big impact on geopolitics in the years to come.