Just as the big summer movie season gets ready to roll, the first teaser for this fall's biggest film has just arrived. "Thor: The Dark World" brings Chris Hemsworth back to the role that made him a superstar for a third time, reuniting him with co-stars Natalie Portman, Anthony Hopkins and Tom Hiddleston. After his team-up with the Avengers last year, this new Thor film looks appropriately serious. The world has changed, the stakes have been raised, and the once-boastful God of Thunder has to step up his game in order to save those he loves.

The film follows May's "Iron Man 3," which will kick off Phase Two of the Marvel Cinematic Universe. While none of Thor's super-buddies are in the sequel (as far as we know), both "Iron Man 3" and "Thor: The Dark World" act as steps toward 2015's "Avengers" sequel. But even without a half dozen heroes running around, "Thor: The Dark World" looks to contain as much epic action as its star-studded predecessor.

Check out the trailer and get a deeper look at the film by keeping an eye out for these five key moments.

The Dark World

The teaser explains the film's title just a tiny bit. "Some believe that before the universe there was nothing," narrates Anthony Hopkins as Odin. "They're wrong. There was darkness, and it has survived." More specifically, darkness has apparently survived in the form of the Dark Elves of Svartalfheim (which also might be the name of your older brother's high school prog-metal band). It appears that they're ready to cause trouble on Earth as well, which definitely won't sit right with Thor, self-appointed protector of Midgard, a fancy name for Earth.

Reunited and It Feels... So Good?

Thor and Jane Foster bonded in a big way during 2011's "Thor," only to have the God of Thunder return to Asgard with no easy way to return. Until he did return, that is, and didn't give Foster so much as a text. Thor returned to Earth in 2012's "Marvel's the Avengers" to prevent an alien invasion in New York City, so it's not like he snuck in unnoticed. And even though he did check up on her while on the S.H.I.E.L.D. Helicarrier, Hemsworth revealed that he's still in the doghouse. But Thor and Jane Foster are together again, this time in Thor's hometown of Asgard. But judging by the teaser, things probably won't go so well.

All Asgard, All the Time

Whereas the first film took place almost entirely in New Mexico, the sequel is definitely out of this world. The trailer splits its time between London and the Nine Worlds, with most of the battles presumably taking place in Asgardian terrain. London only gets screen time when it's getting attacked, making "Thor: The Dark World" the third film of 2012 to make a mess of jolly old England (after "G.I. Joe: Retaliation" and "Star Trek Into Darkness").

In With the New Evil...

The teaser gives us a clear look at Christopher Eccleston as Malekith the Accursed, ruler of the Dark Elves. Half of his face is scarred and charred, a nice nod to his comic counterpart's Two-Face-esque look. He's also up to epic levels of no good, as the teaser seemingly holds him accountable for the destruction of London. Malekith also has Jane Foster in some sort of magical torture hold on the battlefield, which definitely makes him the bad guy to beat. We also get a brief glimpse during Hopkins' narration of a shadowed and statuesque warrior that could be Kurse, played by Adewale Akinnuoye-Agbaje.

And In With the Old Evil

The teaser packs in so many characters (Darcy, Sif and Frigga all pop up) that it's almost easy to forget that one very big, very important, very Tumblr-iffic character was being held for last. Tom Hiddleston returns as Loki after his tour-de-force in "Marvel's the Avengers." This time he's behind another glass prison, looking even worse for wear. "You must be truly desperate to come to me for help," Loki says while sporting an Eddie Vedder-esque hairdo. Thor replies that if Loki betrays him, he'll kill him, proving that the God of Thunder is a big believer of "three strikes and you're out."

Check out everything we've got on "Thor: The Dark World."