'Fringe' Season 4 Episode 20 'Worlds Apart' Preview: Both Universes Must Work Together

Fringe season 4 continues next week with episode 20,"Worlds Apart," and not only are they back in the present after taking a brief look at 2036 in episode 19, "Letters of Transit," but they're also taking a look at both universes.

Fringe Season 4 Episode 20 "Worlds Apart" Promo

"The teams on both sides fight on for a common cause, and there are shocking developments tied to the Cortexiphan children."

While "Letters of Transit" left fans with more questions (especially about what happened to Olivia and what was coming next), "Worlds Apart" will see the Fringe teams with a much more serious problem on their hands than to even start thinking about what could happen years from now. That's because they're going to have to deal with what David Robert Jones is trying to do to both universes.

The Fringe season 4 episode 20 promo for "Worlds Apart" (below) shows that Jones is using Cortexiphan children to trigger events everywhere. As Walter explains it to everyone, he's "trying to collapse both universes to create a world controlled by him." This is something that they're all going to need to work together for, and that should make for some interesting conversation at least at some point. After all, you have to be looking forward to the scene with the Walters sitting side by side.

They do have one option: turning off the machine. Will that work? What will happen when they do? Will they be able to do that, or will something (or someone) get in their way? It doesn't seem like they have much of a choice if that's the only thing they can think of, especially with Olivia's line to end the promo: "In less than six hours, everything we know will cease to exist."