'Avengers 2' is still a long way off. The sequel to one of the biggest films of all-time doesn't hit theaters until 2015 but we've already hit our first major milestone. Writer/Director Joss Whedon has officially submitted his script outline to Marvel. So what's involved?

Rightfully so, Whedon was named one of the "Entertainers of the Year" by Entertainment Weekly and while taking his victory lap in the upcoming issue of the magazine, they note that they met Whedon "just days after he had submitted an outline for the 2015 sequel to 'The Avengers.'"

Of course, a writer submitting an outline for a movie they've signed on to direct is not necessarily breaking news; it's bound to happen eventually. But with 'The Avengers 2,' everything is going to be different.

For one, the 'Avengers 2' outline needs to be submitted this early because of how closely linked some of the films in Phase 2 of the Marvel cinematic universe will be (though Robert Downey, Jr. has repeatedly said that 'Iron Man 3' won't have much of a link to any other Marvel film). Having an outline of what the end game will be helps plan the strategy of the next three years.

Also, with Whedon getting ready to begin work filming the 'S.H.I.E.L.D.' pilot for ABC early next year and will likely need to spend the rest of 2013 writing the actual script and prepping the film to shoot in 2014.

So everything is moving on schedule. But it's exciting to know that somewhere within the top secret confines of Marvel exists a document that spills out one of the biggest sequels in movie history.