This is something I'm looking forward to playing out with someone skilled and knowledgable enough. You dont need to be a historian, just know enough to get by. If you do know a lot, great, but its not mandatory.
World war 3 is being fought, Russia and China are on the move, with some allies in europe helping them. I would play the Captain of a marine company, recently arrived from England with her batallion. Set up in a tent city near the Normandy coast prior to another move closer to the front lines, my Batallion is hit by a new Soviet/Chinese weapon, designed to wipe us out of existence, but it malfunctions. Instead of blinking us out of existence, it transports part of the tent city from 2017 to the exact same spot, to june 6 or 7 1944. Tents, personnell, Tanks, Stryker light armored vehicles, enough to give the German forces that we would be facing a rough time of it. I would be the sole surviving company commander, finding herself without a CO, and in charge of most of three companies, along with armored forces from my time.
We could appear inland of any of the beachheads, to encounter british, US or Canadian forces, find out where we are, make contact with contemporary forces, and work with them to repel advancing german forces and take the objectives even faster.
I do hope that someone reads this, hears it singing to them, and posts.