Princess Celestia looked over the map as the latest reports from the scouts showed the position of the soldiers of Sombra. The mission that Cadance and Shining Armor went on to save the Crystal Empire ended in a failure with Shining Armor barely alive. The crystal ponies have been encase in armor that made them all slaves to Sombra's will and with every captured pony only adds to their numbers. She wished that she and Luna had gone with them and none of this would had happen.
Celestia has been force to over see the battle by leading the fight on the front lines. Her sister Luna is taking care of things back in Canterlot and keeping things running. All the ponies are working in giving what is needed to fight against Sombra, the Element bearers are also helping in the fighting. Pinkie and Rainbow are fighting on the front line as soldiers, Fluttershy has taken up taking care of sheep who's wool are being made into uniforms by Rarity. Then there's Applejack has upgraded her farm to a factory one to mass produce food for the soldiers. It's all that they can do as the elements no longer work for any of them. Without Twilight the elements just no longer work.
Celestia has Luna looking for new element bearers while she fights. But it's slow going with many ponies trying and failing. There is also the humans of the other world who are the counterparts of everypony on this side. She has ponies looking into opening the portal so that the human counterparts of Twilight and the others could use the elements.
But there is also another way. Celestia turn her attention to the book that connects to the one that she gave to Sunset. In all the years that had past since that day, she had never once written to Sunset. Now the only way to contact Sunset and Twilight since they disappeared, is right there. But she is held back by the guilt and shame of all what she could had done and what she should had done. If she could only bring herself to use it and ask the two ponies who she hurt for aide in her time of need. But will the two even answer her call for aide after she had only seen and used them as tools to be used and thrown away when they're no longer needed. (1)