It's pretty self explanatory. Just think of a tagline for the film. Funny taglines are welcome, too.
Here are some I thought of:
-This summer, past and future collide.
-Their past. Their future.
-The future has arrived.
-Singer is back, b*tches!!!
-No more continuity errors.
-This summer, go back to the future!
You wanted to be the hero. Now you gotta pay the price.