I know actually writing this would be much harder than just coming up with a loose idea. But structurally, it would work something like this:
In 2015, a movie comes out that takes place entirely in 2015. In the story, a character travels five years into the future, has some profound experience, and then returns to the present where the ramifications of his future travel profoundly affect him. We never find out exactly what happened in his time jump, and we’re curious, but it’s okay because the present story stands well on its own.
In 2020, the sequel comes out. It takes place entirely in 2020. We finally have caught up with the time traveler, and now we get to see what the heck happened when he got here that affected him in 2015. The story in 2020 also works well on its own, but it sheds new light on events that happened in the 2015 movie.
For bonus points, the time traveller’s 2020 scenes could all be shot in 2015, so the actor will not have aged, but all his costars will. For a more enhanced effect, the movies could be more than five years apart, or the characters could be young so the five years of aging is more dramatically obvious.
Yes, yes, yes, please make this!