Fox's Fringe returns for its fifth and final season next Friday, jumping into the future to wrap up the series by giving us the showdown between humanity and the Observers... not to mention a Walter Bishop just a little unlike any we've seen before. Here are the five things you need to know before next week's season premiere.

The Observers

The villains of the final season have been in the show all along as something more ambiguous and mysterious. It turns out that Fringe take on Marvel's Watcher character (Note the similarity in name and also the bald head look of both) are actually the future descendants of humanity who have evolved a mastery of time (Not only can they travel through time, they seem to have the ability to see time as a whole, and not a linear sequence of events) and traveled to the 21st century having destroyed the Earth from their home 26th century. Think of it as the ultimate Terra Nova joke, if you remember that short-lived show from last year. They have previously seemed to be able to, if not change time - thereby explaining how they could travel to the past and invade Earth - but at least survive changes without being affected themselves, which may be important in future episodes.

The Purge

"The Purge" is the name given to the wholesale slaughter of humanity conducted by the Observers when they arrived on the Earth of 2015. It's unclear how many humans were killed, but it was definitely enough to significantly change the balance of power on the planet - As a result, humans are kept as something between a sub-culture and slaves in the world of 2036, tolerated by the Observers and working in their service much of the time.

The Rebellion

Unsurprisingly, not all humans are happy with the way things have turned out, and many are working together in some kind of underground organization to fight back against the Observer occupation. It's not clear yet exactly how widespread this rebellion is, but in "Letters of Transit," the episode that set up the status quo for the fifth season, we found out that there are rebels working undercover in government agencies, so it's safe to assume that there are allies all over the place, waiting for the moment to strike.

The Fringe

And what of Fringe Division in this Brave New World? Well, they've gone from investigating the unexplained to, it seems, policing humanity on behalf of the Observers. Agent Broyles - a man showing himself more and more capable of apparently turning traitor if it's in his best interests, it seems - is still in charge of the Fringe Division, but I really wouldn't be surprised to find out that he's still a good guy, and just working very deep undercover… but time will tell.

The Daughter

One of the major revelations of "Letters of Transit" was that Etta - the protagonist of the flash-forward hour - was the daughter of Peter Bishop and Olivia Dunham. Like her mother, she appears to have special powers that make her of particular importance to the plot, if not the Observers themselves… But what those powers are, and whether or not she will prove to be the key to whether or not humanity can be saved (The plot hammer would suggest so, but Fringe doesn't always go the obvious route) remains to be seen.