You need to watch the most ingenious time travel movie before it leaves HBO Max this week

The science fiction genre has seen more than its fair share of iconic duos over the years. From Han and Chewie to Kirk and Spock, film and television creators have spent decades using the boundless potential of the sci-fi genre to create some of the most unique and memorable screen pairings in cinema history.

But none of the genre’s many screen duos are as excellent as Bill and Ted.

Appearing on-screen for the first time in 1989, the duo quickly captured the hearts of moviegoers everywhere. Over thirty years later, Bill and Ted remain just as beloved now as they were back then, as is evidenced by the fact that they returned for their third film outing last year in Bill & Ted Face the Music. However, unlike many of the sci-fi genre’s other iconic screen pairs, Bill and Ted are just a couple of high school kids, making their enduring success that much more impressive.

Indeed, on the surface, there doesn’t seem to be anything all that special about them. But that’s far from the truth. Bill and Ted are, in fact, very special, and nowhere is their charm more apparent than in the duo’s first film, 1989’s Bill & Ted’s Excellent Adventure.

Directed by Stephen Herek and written by Chris Matheson and Ed Solomon, Bill & Ted’s Excellent Adventure is one of the most fun and delightfully ludicrous sci-fi films ever made.

Borrowing plot elements from many of the sci-fi classics that came before it, the film follows its two titular characters as they set out to ace their impending high school history assignment by going on a quest to meet (and kidnap) various historical figures. Aided by members of the futuristic society that only exists because of Bill and Ted’s excellent contributions to the world, the friends are given access to a time machine that lets them journey throughout the past, present, and future.

Along the way, they cross paths with some major historical figures, including Napoléon Bonaparte, Abraham Lincoln, Socrates, Billy the Kid, Sigmund Freud, Joan of Arc, and more. It’s an undeniably cooky premise, but the film’s writers, director, and actor all know that — and they fully lean into the complete outrageousness of it all.

Nowhere is that self-awareness more present than in the iconic, over-the-top performances by Alex Winters and Keanu Reeves as Bill and Ted, respectively. The actors are perfectly cast in their roles, and they have such an understanding of the material that they somehow never manage to go too big with their performances — no matter how many times they slowly (but simultaneously) say “Woah” together throughout the film.

Reeves and Winter are, of course, not the film’s only standout cast members. There’s also comedy legend George Carlin as Rufus, an emissary sent from the future to ensure Bill and Ted ace their assignment and keep making music together. Carlin, like Reeves and Winter, has a clear understanding of what he’s meant to do, and he’s dependably hilarious from the moment he delivers the film’s opening monologue all the way to his perfect, final fourth-wall-breaking line.

But what makes Bill & Ted’s Excellent Adventure truly shine is not just its humor or its knowingly cheesy sci-fi premise, but the shocking level of sincerity that runs throughout all of it. The film is deeply uncynical, and it has fun with its characters’ personalities and attitudes without ever ridiculing or minimizing them. It believes in Bill and Ted and the power of their friendship so much that you can’t help but believe too.

Is it any wonder then, after over thirty years after their big-screen debut, audiences still wanted to see more of them?

Bill & Ted’s Excellent Adventure is streaming now on HBO Max.