It looked like the new-gen-only Assassin's Creed game would be sticking only to the time period of the French Revolution. Nope. Somehow, lead character Arno will wind up smack dab in the middle of World War II, with machine guns and everything.
A new trailer for Assassin's Creed Unity shows some kind of spacetime disturbance taking Arno from the time of guillotines to era of Nazi occupation. A late-2013 Ubisoft survey about the future of Assassin's Creed had floated the idea of an AC game letting players explore a city through different era. That's one of the few things that hadn't appeared as a feature for this year's AC games yet, but today's trailer suggests that may indeed be an element of Unity after all.