Gemini Man is not only poised to reestablish Will Smith as a box office champion, but the Ang Lee-directed film is already getting Smith some possible Oscar buzz (despite his A-list status, he's only been nominated twice, and not since 12 years ago). Distributor Paramount Pictures clearly has high hopes for it's box office prospects, and early footage has wowed audience. Adding to the excitement is the fact that Game of Thrones co-creator David Benioff co-wrote the script. Though, unlike so many of today's sci-fi films, Gemini Man is not based on any pre-existing, cult-beloved franchise. Which begs the question, what exactly is it about?

Well, while the story has never been properly delivered to audiences before, that doesn't mean that the idea doesn't have any history. In fact, the script has been bopping around Hollywood as a hot commodity for over twenty-year (originally at Disney, before they sold it to David Ellison's Skydance Media). A murderer's row of leading men including Harrison Ford, Mel Gibson, Clint Eastwood, Nicholas Cage, and Sean Connery were all attached at one point or another, and directors like L.A. Confidential's Curtis Hanson and Top Gun's Tony Scott were interested in directing.

The biggest hold up that kept the project in development hell for over two-decades? No one was quite confident that the technology was available to properly pull it off.

“One of the reasons the movie is finally being made is that the technology is at a place where it’s possible to make it and to make it well,” co-star Mary Elizabeth Winstead told The Wrap last year. “The technology is really kind of experimental in a lot of ways. I think Ang is really pushing the boundaries of filmmaking and the visuals and the experience of watching a movie.

Let's dig into why this story has been a favorite around Hollywood for so long, and why no one has attempted it until now.

The Film Stars Not One, But Two Different Will Smiths at Two Different Ages

Well, technically, it's Will Smith playing two parts, but one with the assistance of digital technology that de-ages by about 25 years.

His main character is Henry Brogan, a government assassin who was once considered the best in the field, but who suddenly has found himself on the outs with his former employers. In fact, his mentor and handler Clay, played by Clive Owen, had Henry cloned to replace him, hence Smith's other, younger character "Junior." (If you haven't figured out why it's called Gemini Man yet, clearly you're no fan of astrology. Gemini is the sign represented by twins).

As It Turns Out, The Dystopian Government Henry Used to Work With Is Evil

Henry isn't entirely sure why he's been dumped from his government assassin job, but of course that government now wants him dead. Naturally, they send his younger clone after him, but while Junior has the advantage of youth, Henry has experience and wisdom and is able to predict most of Junior's move. As per the trailer, at first, at least, Junior isn't exactly sure who he is sent to kill in the first place, let alone that it's the man he was cloned from.

Mary Elizabeth Winstead and Benedict Wong Play Some of Will Smith's Former Hitman Friends

Winstead plays Danny Zakarweski, who still helps Henry even after he's marked for death. Wong plays another associate, but it's unclear where his allegiances lie.

A Lot of Dramatic Heft Has Been Added In the Past 20 Years

The movie's basic plot of "Old Hitman Faces Off Against Younger Clone" is pretty clear and intriguing, but there was always the risk that it might just come off like a more high-concept but overall lesser version of Face/Off. Indeed, reviews of earlier versions of the script that have leaked online over the years haven't always been positive, with the project being dinged for clichés and flimsy character development.

Benioff, however, was brought in to re-writer the script well before his GoT heyday, and it's his version of the script that still stands as the basis for what was filmed.

Add in Lee, the Oscar winning director who has proven himself with action and high-concept CGI (see: Crouching Tiger, Hidden Dragon and The Life of Pi), but who can also make an affecting low-budget film with nothing more than an emotional story and some good acting (see: Brokeback Mountain), and we're sure to get something deeper than just a movie destined for weekend afternoon viewing on basic cable. There's certainly a lot to work with here: evil governments, an older man looking back and dealing (on multiple levels) with his youth, and his adversary coming to terms with the fact that he's a clone not only created to kill, but, specifically, kill the man he's cloned from.

When it arrives in theaters on October 11th, expect not only some cool CGI and high-concept action sequences, but if the buzz holds true, some solid drama as well.

Oh, There is a Sizzle Reel For the Proposed Clint Eastwood Version, As Well

At one point Joe Carnahan was attached to direct and wanted Eastwood to star, so using clips from Eastwood's storied film career, he put together a sizzle reel for his vision for the project. Please, enjoy.

Related: What Will David Benioff and D.B. Weiss Bring to Netflix For $200 Million?