What exactly is the ninth film by Quentin Tarantino, Once Upon a Time in Hollywood, about? We're still not really sure. Unlike every other Tarantino film since Jackie Brown, the screenplay has not leaked onto the Internet, and the film's advertising is keeping details close to the vest.

The teaser trailer introduced us to the main characters, actor Rick Dalton (Leonardo DiCaprio) and his stunt double Cliff Booth (Brad Pitt), while showing off the 1969 Los Angeles setting. What it didn't do is tell us anything about the plot. We know the film is dealing with Charles Manson in some way, and that Margot Robbie is playing Sharon Tate, an actress who was murdered by Manson's followers, but the film isn't supposed to be more about the general time frame than about the Manson family directly.

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Given Tarantino's penchant for ahistoricity, there have been rumors that this could be an Inglourious Basterds-esque revenge feature in which Tate manages to survive and gets revenge on Manson. How Rick and Cliff fit into the rumored story is unclear.

There's also reason to suspect that this Hollywood tale will end up commenting on #MeToo in some way. Given this is Tarantino's first studio film made since his long-time producer Harvey Weinstein was exposed as a predator, and that Tate's infamous husband Roman Polanski is also a character in the film, that's a dimension people will be paying close attention to.

Also, it might involve superheroes. Sort of.

Even by Tarantino's fluid sense of genre, it would be way out of left field if Once Upon a Time in Hollywood was actually a superhero movie. It would not be unexpected, however, for it to engage with or reference superhero stories the same way Tarantino's films have always dealt in pop culture geekery.

From the trailer for Once Upon a Time in Hollywood, we've spotted a reference that indicates a superhero TV series might play a role in the movie's story. To be specific, we're looking at a reference to The Green Hornet.

Bruce Lee Green Hornet Once Upon a Time in Hollywood

One scene in the trailer prominently features the legendary martial artist Bruce Lee, as played by Mike Moh, wearing a distinctive double-breasted black tunic and gloves. This is the same costume (minus the hat and the mask) that the real Bruce Lee wore while playing Kato in The Green Hornet TV series.

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This reference is something of a surprise for a movie that's been almost entirely talked up based on its 1969 setting, given The Green Hornet ceased production two years earlier in 1967. This could be a flashback scene, or it could be that Lee is still wearing the costume years later simply because it's an awesome costume.

Bruce Lee wouldn't seem to be a major character in Once Upon a Time in Hollywood. Moh's role had mostly been ignored by the press before this teaser trailer dropped. From the teaser, though, it seems like he might have a memorable part in the film. Columbia Pictures' official summary says the movie has "a large ensemble cast and multiple storylines." While DiCaprio, Pitt and Robbie are the clear leads out of this wide ensemble, Moh will likely have some noteworthy role to play amidst the huge ensemble.

Will the production of The Green Hornet be a significant part of this role? We're not sure, and somewhat skeptical. It seems more likely the focus of the Bruce Lee story in the movie will be on Roman Polanski's conspiracy theory that Lee was responsible for Sharon Tate's murder.

Even so, the costume homage is still a fun nod to Bruce Lee's past, and cinema's history with the superhero genre.