The Premise:
A notorious supervillain has got his hands on time travel technology. He’s spent several months (or years? Decades?) just wandering around time and space, observing, studying, and taking notes. He’s even tried making subtle changes at key times, just to see what the effects would be. Now, after his long and arduous research, he is ready to strike. He is assembling a team of like-minded individuals to strike at key points in history to change the shape and flow of time and space.