Seth Gabel and Anna Torv

Serve. Obey. Heed. No Hope. We're guessing Fringe is trying to say something and it's not just "Hey, Fox, renew us already!" Nope, this is all about #April20thIsTheNineteenth, the viral campaign centered on Friday's episode — the 19th of the season, which has traditionally been Fringe's craziest hour each year.

Over the last few weeks, three mind-boggling and super mysterious trailers have hit the interwebs filled with shaky clips from the Observer-iffic, future-set "Letters of Transit" and embedded with clues to a URL that will link fans to a final video that's sure to shake whatever universe you're watching from. But the collection is incomplete, folks... until now.

Today, TV Guide Magazine is proud to unveil the exclusive fourth trailer, featuring the last bit of info you need to find the fifth trailer, as well as a sneak peek at guest star Henry Ian Cusick making his first return to the world of J.J. Abrams since Desmond left Lost island. So watch away, kids! And keep an eye on this site... more info on that fifth trailer is coming soon!

Are you excited for this season's 19th episode? What do you think is going on here?

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