A World not Worth Living

To stop a war from ever happening, Hiro, Violet and Wilbur travel back in time to before it began.
But instead of completing their mission, none of them remember the events of the future and think that everything happening is a coincidence. With no memory of the future, the three will have to unite their families and not fail this time.
Big Hero 6, The Incredibles and Meet the Robinsons Crossover