You need to watch the most innovative sci-fi steampunk movie on HBO Max ASAP

Sir Arthur Conan Doyle created the original sci-fi hero.

The author’s famous Victorian detective used “the science of deduction” to solve mysteries and battle villains. His stories are, arguably, science fiction by default, simply because their sleuth of a protagonist used science in a fictional way.

We’re talking about the one and only Sherlock Holmes, whose stories also inspired the creation of several other sci-fi icons, from Batman to Spock and beyond. But, even if you don’t buy all that, there are a few versions of Holmes who seem to exist in soft sci-fi alternate realities. One of the best and most underrated was Robert Downey Jr.’s turn as the great detective in the 2009 steampunk romp simply titled Sherlock Holmes.

It’s now streaming on HBO Max and totally worth your time. Here’s why. The game’s afoot! Only mild spoilers ahead for Sherlock Holmes (2009).

What’s the deal with Robert Downey Jr.’s Sherlock Holmes?

The year 2009 was amazing for big movies. In May, you had the groundbreaking J.J. Abrams Star Trek reboot, and by Christmas, you had Avatar. In other words, there was a lot of competition to catch the eyes of sci-fi-loving moviegoers.

Starring Robert Downey Jr. and Jude Law as Sherlock Holmes and Doctor Watson, the Guy-Ritchie-directed film decided to transform the public perception of Holmes from a brooding thinker to a man of kick-ass action.

The keyword here, though, is perception. Although Holmes and Watson are beating-down people in more hardcore ways than in the majority of the Conan Doyle stories, the idea of Holmes being an excellent fighter did originate on the page, not the screen. In “The Empty House,” Sherlock speaks to Watson of his use of “baritsu,” a semi-fictional form of wrestling that he used to defeat Moriarty at the Reichenbach Falls in “The Final Problem.” Holmes also beats up a dude in a bar in the short story "The Solitary Cyclist,” which was faithfully recreated by Jeremy Brett in the 1984 Granada TV adaptation.

And, although you may associate Sherlock Holmes with his famous deerstalker hat, you won’t find Downey Jr. wearing such a hat in the 2009 film, nor its 2011 sequel, Game of Shadows. This, too, is compatible with the books and stories by Sir Arthur Conan Doyle. If anyone tells you that the RDJ take on Holmes is somehow a contradiction from the books, they’re dead wrong. This darker, more violent version of Holmes existed in those pages, too. We just see more of that side of him in this film.

Why Sherlock Holmes is an underrated steampunk classic

Despite presenting a very angular take on a version of Holmes who could exist in the Conan Doyle stories, the plot of Sherlock Holmes itself is not taken from any of the canonical 56 short stories or four novels. Yes, Irene Adler (Rachel McAdams) comes from the famous story, “A Scandal in Bohemia,” but this movie implies the story has already happened. Instead, the RDJ’s Holmes is battling a conspiracy that involves a cult trying to combine science and magic and a bad guy who has a scheme that borders on something stolen from a James Bond villain.

In both of these cases, steampunk anachronisms rule the day. We’re not dealing with something like The League of Extraordinary Gentlemen here, but it’s not far off. Both the climax and several aspects of the film’s plot revolve around technology that didn’t exist in 1890. This isn’t as distracting as it might seem, though — be warned — the primary plot of Lord Blackwood (and by extension, Moriarty) is directly the result of anachronistic tech.

Because steampunk technology is what makes Sherlock Holmes tick (at least with some of its story), the film weaves a kind of alternate universe version of the great detective. Guy Ritchie's kinetic directorial style also gives the entire movie a jaunty, contemporary feeling, adding to the bewilderment that what you’re watching is a kind of period piece but, perhaps, from an alternate timeline.

To be clear, Sherlock Holmes never goes full sci-fi, but the aesthetic gets pretty darn close. It presents a familiar world that seems more dangerous and fantastical than the one Conan Doyle created.

On several occasions, Robert Downey Jr. has gone on record saying he wants to build out an expanded universe of Holmes films. Speaking about the possibility of a third Holmes sequel in 2020, Downey Jr. said, “Why do a third movie if you're not going to be able to spin off into some real gems of diversity and other times and elements?”

If he does get his wish, and more Holmes films are on their way, revisiting this excellent and underrated film is more than just fun... it’s elementary.

Sherlock Holmes (2009) is now streaming on HBO Max.